Thin the app's comments

The same pass the server had, on the Kotlin side: comments restating what
the code says are gone, and the ones recording a measurement, a constraint
or an incident are kept but cut to a few lines each. 6540 comment lines to
5674, and 920 lines off the app.

Two doc comments had drifted onto the item above the one they describe --
`contextAfter`'s onto `sessionWorking` in Events.kt, and `UsageMonitor`'s
equivalent on the server was fixed in the previous commit. Each is back on
its own item, which is the only non-comment line this diff moves.

The comments are reflowed to the column limit at their own indentation:
several were written wide, and ktfmt re-wrapped them into lines holding a
single orphan word. `/tmp` script, not kept -- ktfmt is idempotent over the
result, which is the check.

Left alone deliberately: this codebase's remaining comment density is high
because the comments carry things the code cannot say -- what a null means,
what a number was measured against, which bug a guard exists for. Of the
238 one-line doc comments in the app, five were pure restatement of the
name and were removed; the rest each say something the signature does not.

ktfmtFormat, compileDebugKotlin, lintDebug and testDebugUnitTest pass;
cargo test (127), clippy --all-targets and fmt still clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/androidApp/src/main/kotlin/com/example/aiapp/Ansi.kt

@@ -13,9 +13,8 @@ import androidx.compose.ui.text.style.TextDecoration
  *
  * Its own palette rather than the syntax one: a program that prints in red has chosen red, where a
  * highlighter's colours are this app's reading of somebody else's code. They come out of the same
- * Catppuccin values (see `ansiPalette` in `Theme.kt`) so nothing on screen is a colour from
+ * Catppuccin values so nothing on screen is a colour from somewhere else, but the two are not one
- * somewhere else, but the two are not one table and must not become one -- adding a syntax role to
+ * table -- adding a syntax role to this list would silently move `ls`'s directory blue.
- * this list would silently move `ls`'s directory blue.
  */
 data class AnsiPalette(
     /** Indexes 0-7, then 8-15 bright, in the terminal's own order. */
@@ -30,19 +29,18 @@ data class AnsiPalette(
  * What a tool printed, with its terminal styling applied and everything else taken out.
  *
  * Bash output arrives exactly as the program wrote it, escape sequences included, and drawn
- * verbatim those are line noise in the middle of the thing being read: `ESC[0;32m` in front of
+ * verbatim those are line noise in the middle of the thing being read. Stripping them all would be
- * every green word. Stripping them all would be the other half-answer -- colour is often the whole
+ * the other half-answer -- colour is often the whole of what a diff or a test run is saying.
- * of what a diff, a test run or a linter is saying.
  *
- * So the sequences that decide how text *looks* become spans, and every other one is dropped.
+ * So the sequences that decide how text *looks* become spans, and every other one is dropped rather
- * Dropped rather than shown, because the rest move a cursor around a grid this is not: a transcript
+ * than shown: the rest move a cursor around a grid this is not, and "go to column 40" has no
- * is a scrolling document, and "go to column 40" has no meaning here that is better than nothing.
+ * meaning in a scrolling document.
  *
  * A carriage return is honoured the way a terminal honours it: what was written since the last line
  * break is thrown away and the line starts again. That is what makes a progress bar show its final
- * state rather than every state it passed through, which was tens of lines run together.
+ * state rather than every state it passed through.
  *
- * Not a composable, and the palette is a parameter: this can then be remembered against the text it
+ * Not a composable, and the palette is a parameter, so this can be remembered against the text it
  * parsed rather than re-run on every recomposition of the card holding it.
  */
 fun ansiStyled(text: String, palette: AnsiPalette): AnnotatedString {
@@ -71,10 +69,9 @@ fun ansiStyled(text: String, palette: AnsiPalette): AnnotatedString {
                         if (final == 'm') sgr = sgr.apply(params, palette)
                     }
             }
-            // A bare carriage return rewrites the line. One before a newline is the other half
+            // A bare carriage return rewrites the line. One before a newline is the other half of a
-            // of a Windows line ending: it rewrites nothing, and it is dropped rather than kept,
+            // Windows line ending: it rewrites nothing, and it is dropped rather than kept, since
-            // since that pair is one line break and the return itself would draw as a stray
+            // that pair is one line break.
-            // control character.
             c == '\r' && text.getOrNull(at + 1) != '\n' -> {
                 flush()
                 dropLine(runs)
@@ -82,8 +79,8 @@ fun ansiStyled(text: String, palette: AnsiPalette): AnnotatedString {
             }
             c == '\r' -> at++
             // Everything printable, plus the two control characters that are layout rather than
-            // terminal commands. A stray bell or backspace goes for the same reason a cursor
+            // terminal commands. A stray bell or backspace goes for the same reason a cursor move
-            // move does.
+            // does.
             c >= ' ' || c == '\n' || c == '\t' -> {
                 plain.append(c)
                 at++
@@ -129,9 +126,8 @@ private const val BELL = '\u0007'
  * Steps over the escape sequence starting at [at], reporting a CSI's parameters and final byte.
  *
  * One reader for every kind, because the point is to *leave* them all behind: a sequence this did
- * not recognise would otherwise have its body printed as ordinary text, which is worse than the
+ * not recognise would otherwise have its body printed as ordinary text. Three shapes -- the CSI
- * escape it was meant to remove. Three shapes -- the CSI (`ESC [ … letter`), the string escapes
+ * (`ESC [ … letter`), the string escapes which run to a terminator, and the two-character ones.
- * (OSC, DCS, APC, PM) which run to a terminator, and the two-character ones.
  */
 private inline fun skipEscape(text: String, at: Int, onCsi: (String, Char) -> Unit): Int {
     val next = text.getOrNull(at + 1) ?: return at + 1
@@ -140,9 +136,9 @@ private inline fun skipEscape(text: String, at: Int, onCsi: (String, Char) -> Un
             var end = at + 2
             while (end < text.length && text[end] !in CSI_FINAL) end++
             if (end >= text.length) {
-                // Cut off mid-sequence, which is what a stream that has not finished arriving
+                // Cut off mid-sequence, which is what a stream that has not finished arriving looks
-                // looks like: drop the fragment rather than printing it, and the whole sequence
+                // like: drop the fragment rather than printing it, and the whole sequence arrives
-                // arrives with the next delta.
+                // with the next delta.
                 text.length
             } else {
                 onCsi(text.substring(at + 2, end), text[end])

app/androidApp/src/main/kotlin/com/example/aiapp/Api.kt

@@ -6,26 +6,23 @@ import java.net.URL
 import org.json.JSONArray
 import org.json.JSONObject
 
-// The REST half of the backend's surface (see server/src/routes.rs for the
+// The REST half of the backend's surface (see server/src/routes.rs for the table); the SSE half is
-// table); the SSE half is EventStream.kt. All blocking network calls --
+// EventStream.kt. All blocking network calls -- invoke from a background dispatcher. Each throws
-// invoke from a background dispatcher. Each throws ApiException on failure,
+// ApiException carrying the server's own explanation where it sent one, since those messages are
-// carrying the server's own explanation where it sent one, since those
+// written to be read on this screen.
-// messages are written to be read on this screen.
 
-// Shared with EventStream.kt, which connects the same way but then reads
+// Shared with EventStream.kt, which connects the same way but then reads without a deadline.
-// without a deadline.
 const val CONNECT_TIMEOUT_MS = 5000
 private const val READ_TIMEOUT_MS = 5000
 
 /**
  * A request that did not produce what it asked for, carrying the server's own wording where it sent
- * some -- those messages are written to be read on the screen that made the call.
+ * some.
  *
  * [status] is the HTTP status where there was a response at all, and null where the server was
  * never reached. Callers that need it need it because the *same* failure is two different things to
- * do: a 409 from a write is "somebody else changed this, here are three ways out", where every
+ * do: a 409 from a write is "somebody else changed this, here are three ways out". Nothing should
- * other refusal is a message to show. Nothing should branch on it to decide what to *say* -- the
+ * branch on it to decide what to *say* -- the message is what says that.
- * message is what says that.
  */
 class ApiException(message: String, val status: Int? = null, cause: Throwable? = null) :
     Exception(message, cause)
@@ -33,10 +30,10 @@ class ApiException(message: String, val status: Int? = null, cause: Throwable? =
 /**
  * Runs one request against the backend, with the pinned TLS setup, the bearer token, and the
  * failure translation every call needs. [readBody] gets the connected, already-status-checked
- * connection to read from.
+ * connection.
  *
  * @param readTimeoutMs how long to wait on the response body. The SSE stream doesn't come through
- *   here -- an event stream has no bounded read time (see EventStream.kt).
+ *   here -- an event stream has no bounded read time.
  */
 fun <T> requestFromServer(
     settings: ServerSettings,
@@ -44,9 +41,9 @@ fun <T> requestFromServer(
     method: String = "GET",
     jsonBody: String? = null,
     /**
-     * A request body written as it is produced -- the upload path. Content type, and a writer
+     * A request body written as it is produced -- the upload path. Sent chunked, since what a
-     * handed the connection's stream. Sent chunked, since what a writer will produce is not known
+     * writer will produce is not known up front and the point is that a file never sits whole in
-     * up front and the point is that a file never sits whole in memory on this side.
+     * memory.
      */
     streamBody: Pair<String, (java.io.OutputStream) -> Unit>? = null,
     readTimeoutMs: Int = READ_TIMEOUT_MS,
@@ -87,9 +84,8 @@ fun <T> requestFromServer(
     } catch (e: ApiException) {
         throw e
     } catch (e: IOException) {
-        // Surfacing the real exception (rather than one canned message for
+        // Surfacing the real exception rather than one canned message for every failure mode is
-        // every failure mode) is what lets this be diagnosed on a device
+        // what lets this be diagnosed on a device with no logcat access.
-        // with no logcat access.
         throw ApiException(
             "Couldn't reach the server at ${settings.baseUrl} " +
                 "(${e::class.simpleName}: ${e.message}) -- is ai-server running, and is " +
@@ -107,11 +103,9 @@ fun <T> requestFromServer(
     }
 }
 
-/** The response body as one JSON object. */
 private fun HttpURLConnection.jsonObject(): JSONObject =
     JSONObject(inputStream.bufferedReader().readText())
 
-/** The response body as a JSON array of objects, each mapped through [parse]. */
 private fun <T> HttpURLConnection.jsonObjects(parse: (JSONObject) -> T): List<T> =
     JSONArray(inputStream.bufferedReader().readText()).mapObjects(parse)
 
@@ -120,21 +114,16 @@ private fun <T> JSONArray.mapObjects(parse: (JSONObject) -> T): List<T> =
 
 private fun JSONArray.strings(): List<String> = (0 until length()).map { getString(it) }
 
-/** Percent-encodes a value going into a query string. */
 private fun String.urlEncoded(): String = java.net.URLEncoder.encode(this, Charsets.UTF_8.name())
 
-// One row of GET /sessions. A session names the machine it runs on and
+// One row of GET /sessions. A session names the machine it runs on and which of that machine's
-// which of that machine's providers it runs.
+// providers it runs.
 data class SessionSummary(
     val id: String,
     /**
      * Id of the machine this session runs on. Only ever used to *address* that machine -- to pick
-     * this session's row out of the per-machine usage snapshots for the header's five-hour bar.
+     * this session's row out of the per-machine usage snapshots. Never shown; [setupName] is what a
-     *
+     * reader sees, and holding both invites showing the wrong one.
-     * It was deliberately left out until 2026-08-29, on the grounds that nothing here addressed a
-     * setup and holding both the id and the name invited showing the wrong one, which had already
-     * happened once. Something addresses one now, so the reason lapsed rather than being overruled.
-     * The guard that replaces it is the rule below: never show this.
      */
     val setup: String,
     /** The machine's current label. This is the one to display; [setup] is never shown. */
@@ -147,9 +136,8 @@ data class SessionSummary(
      * provider's kind rather than here from its name.
      *
      * What it licenses is narrow, and the delete dialog is worded to match: the driver keeps its
-     * own record of the conversation somewhere this app's delete does not reach. It is not a
+     * own record somewhere this app's delete does not reach. It is not a promise that the file is
-     * promise that the file is still there, and re-importing is not a restore -- this app's
+     * still there, and re-importing is not a restore.
-     * transcript holds things that record does not.
      */
     val keepsOwnTranscript: Boolean,
     /** How much the session asks before acting; null when it was never set. */
@@ -162,35 +150,32 @@ data class SessionSummary(
      * Whether this session announces itself when it wants attention.
      *
      * Reported rather than assumed, for the same reason [permissionMode] is: a switch that draws
-     * itself from a default is one you can turn off while believing you are reading it. Defaults to
+     * itself from a default is one you can turn off while believing you are reading it.
-     * on when a backend is too old to say, which matches what that backend actually does.
      */
     val notify: Boolean,
     /**
      * The directory the session works in, or null where it was never given one.
      *
-     * Null is not "the home directory": it is the session never having been told, and what the
+     * Null is not "the home directory": it is the session never having been told. Shown as unset
-     * process then starts in belongs to whatever launches it. Shown as unset rather than filled in
+     * rather than filled in with a guess, so a reader changing it is choosing rather than
-     * with a guess, so a reader changing it is choosing rather than confirming.
+     * confirming.
      */
     val cwd: String?,
     /**
-     * How much context this session is holding, as the server last measured it -- see
+     * How much context this session is holding, as the server last measured it.
-     * `SessionEvent.UsageDelta`.
      *
      * Null where nothing has been measured: a session that has not run a turn, a provider that does
      * not report usage, or a clear nobody has run a turn since. That is not zero, and the status
      * row says so in words rather than drawing an empty context for a conversation that may be
-     * nearly full.
+     * full.
      */
     val contextTokens: Long?,
     /**
      * The longest edge an image should have when it reaches this session, or null where the
      * provider has no limit.
      *
-     * Null and "a big number" are different answers, and only the first stays true: a provider that
+     * Null and "a big number" are different answers, and only the first stays true. Decided by the
-     * does not care about size should not be given a threshold this app invented. Decided by the
+     * server because that is where a provider's kind is known.
-     * server because that is where a provider's kind is known -- see `uploadPickedImage`.
      */
     val maxImageEdge: Int?,
     val status: String,
@@ -225,18 +210,16 @@ fun fetchSessions(settings: ServerSettings): List<SessionSummary> =
  *
  * For screens whose controls are *set to* something rather than merely showing it. A screen opened
  * from a list row carries the row the list last fetched, which is a snapshot: fine for a title,
- * wrong for a switch, since a switch drawn from a stale row shows a position that may have been
+ * wrong for a switch, since a stale row shows a position that may have been changed since.
- * changed since -- here or on another device -- and nothing on screen says which.
  */
 fun fetchSession(settings: ServerSettings, sessionId: String): SessionSummary =
     requestFromServer(settings, "/sessions/$sessionId") { parseSession(it.jsonObject()) }
 
-// What the server offers, so the spawn screen has no hardcoded lists: a
+// What the server offers, so the spawn screen has no hardcoded lists: a setup added to the server's
-// setup added to the server's config.ron appears here with no app rebuild.
+// config.ron appears here with no app rebuild.
 //
-// One list rather than two. A provider only exists on a machine that has
+// One list rather than two. A provider only exists on a machine that has it installed, so offering
-// it installed, so offering machines and providers as independent choices
+// machines and providers as independent choices would offer pairs that cannot work.
-// would offer pairs that cannot work.
 data class Provider(val name: String, val kind: String, val models: List<String>)
 
 /**
@@ -275,7 +258,7 @@ fun fetchSetups(settings: ServerSettings): List<Setup> =
  * A Claude Code session already on a machine, which can be continued here.
  *
  * Identified by [id] and never by a path. The server resolves which file that is, so this app has
- * no way to ask it to read one -- the same rule that keeps a provider's command out of this client.
+ * no way to ask it to read one.
  */
 data class Importable(
     val id: String,
@@ -284,19 +267,15 @@ data class Importable(
     val modified: Double,
     val lines: Int,
     /**
-     * Size of the session file in bytes.
+     * Size of the session file in bytes. Worth a place on the row because it is the only thing
-     *
+     * there that predicts what continuing the session costs, and the line count does not: these
-     * Worth a place on the row because it is the only thing there that predicts what continuing the
+     * transcripts embed screenshots as base64, so a single line can be a megabyte.
-     * session costs, and the line count does not: these transcripts embed screenshots as base64, so
-     * a single line can be a megabyte.
      */
     val bytes: Long,
     /**
-     * Tokens the model was holding at the last turn, or null if no turn has recorded any.
+     * Tokens the model was holding at the last turn, or null if no turn has recorded any. It
-     *
+     * disagrees with [bytes] in the direction that matters: most of a large transcript is usually
-     * The number that predicts what continuing this session costs. It disagrees with [bytes] in the
+     * history from before a compaction, which the model is no longer given.
-     * direction that matters: most of a large transcript is usually history from before a
-     * compaction, which the model is no longer given.
      */
     val contextTokens: Long?,
     /** Whether [title] is a name somebody chose rather than the last thing said in the session. */
@@ -305,17 +284,15 @@ data class Importable(
      * Whether a Claude Code is running this session right now.
      *
      * "unknown" is a third answer and not a synonym for "no": the machine may keep no record of
-     * what is running, and a session that cannot be checked is not a session that is free. The
+     * what is running. The server refuses an import of a "yes"; the row says so before you press
-     * server refuses an import of a "yes"; the row says so before you press it.
+     * it.
      */
     val inUse: String,
     /**
-     * What this server is doing to the session right now -- "importing" or "deleting" -- or null
+     * What this server is doing to the session right now -- "importing" or "deleting" -- or null.
-     * when nothing is.
      *
      * The server's answer rather than the phone's, because the work outlives the screen that asked
-     * for it: leaving the import list and coming back has to show what is still running, and a
+     * for it: a phone that was asleep never saw the events that said so.
-     * phone that was asleep or out of range never saw the events that said so.
      */
     val pending: String?,
     /**
@@ -328,7 +305,7 @@ data class Importable(
 /**
  * One frame of `GET /setups/{id}/importable/events`: an operation starting, finishing or failing.
  *
- * [operation] is only set by a start, and [message] only by a failure -- the three states are every
+ * [operation] is only set by a start and [message] only by a failure -- the three states are every
  * way an operation can be, and each carries exactly what that state knows.
  */
 data class ImportableChange(
@@ -348,20 +325,18 @@ fun parseImportableChange(payload: String): ImportableChange? =
             message = frame.optString("message").takeIf { it.isNotEmpty() },
         )
     } catch (_: org.json.JSONException) {
-        // A frame this build does not understand is not a reason to drop the stream: the listing
+        // A frame this build does not understand is not a reason to drop the stream: the listing is
-        // is the truth and will say what happened whatever this missed.
+        // the truth and will say what happened whatever this missed.
         null
     }
 
 /**
  * What a machine has that could be continued.
  *
- * The slowest call this app makes, and it was the only expensive one left on the 5 second default —
+ * The slowest call this app makes, and it was the only expensive one left on the 5 second default
- * which is how it came to time out against a server that was answering perfectly well. Listing
+ * -- which is how it came to time out against a server answering perfectly well. Listing means
- * means reading every transcript Claude Code has ever written: about four seconds against a
+ * reading every transcript Claude Code has ever written: about four seconds against a gigabyte of
- * gigabyte of them before the tunnel adds anything, and that figure grows with every session
+ * them before the tunnel adds anything. A timeout is for a server that has stopped answering.
- * anybody has. A timeout is for a server that has stopped answering, so it is set well clear of how
- * long the work takes rather than just above it.
  */
 fun fetchImportable(settings: ServerSettings, setup: String): List<Importable> =
     requestFromServer(settings, "/setups/$setup/importable", readTimeoutMs = 60000) {
@@ -373,13 +348,11 @@ fun fetchImportable(settings: ServerSettings, setup: String): List<Importable> =
                 modified = session.optDouble("modified", 0.0),
                 lines = session.optInt("lines", 0),
                 bytes = session.optLong("bytes", 0L),
-                // Absent means nothing has been measured -- which is not a context of zero, so
+                // Absent means nothing has been measured, which is not a context of zero.
-                // it stays null and the row simply does not claim a figure.
                 contextTokens =
                     if (session.isNull("contextTokens")) null
                     else session.optLong("contextTokens").takeIf { it > 0L },
-                // Absent means an older backend that cannot answer, which is exactly what
+                // Absent means an older backend that cannot answer, which is what "unknown" says.
-                // "unknown" says -- so the default is the honest one rather than "no".
                 inUse = session.optString("inUse", "unknown"),
                 named = session.optBoolean("named", false),
                 pending = session.optString("pending").takeIf { it.isNotEmpty() },
@@ -528,8 +501,7 @@ fun sendMessage(
  *
  * Throws rather than returning an outcome, because both ways of failing are things the reader has
  * to be told: 409 means the session was already given it, and 404 means nothing is waiting under
- * that id. The bubble disappearing is the success case and it arrives on the event stream, not from
+ * that id. The bubble disappearing arrives on the event stream, so every device drops it.
- * here -- every device drops it, not only the one that tapped.
  */
 fun unqueueMessage(settings: ServerSettings, sessionId: String, messageId: String) {
     requestFromServer(
@@ -543,13 +515,11 @@ fun unqueueMessage(settings: ServerSettings, sessionId: String, messageId: Strin
 /**
  * Moves a session to a different working directory.
  *
- * The server checks the directory is there on that machine and refuses if it is not -- a mistyped
+ * The server checks the directory is there and refuses if it is not -- a mistyped path accepted
- * path accepted here would surface much later, as a session that would not start, with nothing
+ * here would surface much later, as a session that would not start.
- * pointing at the typo.
  *
  * Its process is **stopped**, because a working directory is settled when the process is spawned.
- * The next thing said to the session starts it again in the new one, which is this app's rule for a
+ * The next thing said to the session starts it again in the new one.
- * session with no process everywhere else.
  */
 fun setSessionCwd(settings: ServerSettings, sessionId: String, cwd: String) {
     requestFromServer(
@@ -593,8 +563,8 @@ fun uploadAttachment(
                     write(out)
                     out.write(tail)
                 },
-        // Long: a trace is hundreds of megabytes, and the server copies it on to a remote
+        // Long: a trace is hundreds of megabytes, and the server copies it on to a remote machine
-        // machine before answering.
+        // before answering.
         readTimeoutMs = 600000,
     ) { connection ->
         connection.jsonObject().getString("id")
@@ -605,8 +575,7 @@ fun uploadAttachment(
  * One entry of a directory on the machine a setup names.
  *
  * [kind] is the *target's* where the entry is a symlink, so a link to a directory descends; [link]
- * still says it is one. Neither is worked out here -- the machine answers both, because it is the
+ * still says it is one. Neither is worked out here -- the machine answers both.
- * only thing that can.
  */
 data class DirEntry(
     val name: String,
@@ -625,10 +594,10 @@ data class Listing(val path: String, val entries: List<DirEntry>)
 /**
  * What reading a file produced.
  *
- * Four cases, because they are four different things to draw and none of them is an error the
+ * Four cases, because they are four different things to draw and none is an error the screen can
- * screen can shrug off: content, something that is not text, something too big to have sent, and
+ * shrug off: content, something that is not text, something too big to have sent, and (as
- * (as [ApiException], not a case here) the machine's own refusal. A file with nothing in it is
+ * [ApiException]) the machine's own refusal. A file with nothing in it is [FileContent.Text] with
- * [FileContent.Text] with an empty string -- which is what it is, and not the same as any of these.
+ * an empty string, which is what it is.
  */
 sealed class FileContent {
     abstract val path: String
@@ -688,9 +657,8 @@ fun fetchFile(settings: ServerSettings, setup: String, path: String): FileConten
     requestFromServer(
         settings,
         "/setups/${setup.urlEncoded()}/file?path=${path.urlEncoded()}",
-        // A megabyte over the tunnel, and a `stat` plus a `sha256sum` on the far machine before
+        // A megabyte over the tunnel, and a `stat` plus a `sha256sum` on the far machine before any
-        // any of it moves. Well clear of that rather than just above it -- a timeout is for a
+        // of it moves. Well clear of that rather than just above it.
-        // server that has stopped answering.
         readTimeoutMs = 60000,
     ) { connection ->
         val body = connection.jsonObject()
@@ -709,8 +677,7 @@ fun fetchFile(settings: ServerSettings, setup: String, path: String): FileConten
             "binary" -> FileContent.Binary(at, size, modified)
             "tooBig" -> FileContent.TooBig(at, size, modified)
             // A backend that has learned a fifth answer. Reported rather than guessed at: picking
-            // the nearest of the four would draw something confident about a state this app has
+            // the nearest of the four would draw something confident about a state never seen.
-            // never seen.
             else ->
                 throw ApiException(
                     "The server described this file as \"$kind\", which this app does not know how to show."
@@ -721,9 +688,8 @@ fun fetchFile(settings: ServerSettings, setup: String, path: String): FileConten
 /**
  * Replaces a file's contents, but only while it still hashes to [ifSha256].
  *
- * The refusal is a 409 and arrives as an [ApiException] carrying the server's wording, which is
+ * The refusal is a 409 carrying the server's wording, which is what the conflict dialog shows -- an
- * what the conflict dialog shows -- an agent editing the same file while somebody reads it is the
+ * agent editing the same file while somebody reads it is the ordinary case here.
- * ordinary case here, not the exotic one.
  */
 fun writeFile(
     settings: ServerSettings,
@@ -770,7 +736,6 @@ fun createDir(settings: ServerSettings, setup: String, path: String) {
     ) {}
 }
 
-/** Fetches an image the transcript references (produced or uploaded). */
 fun fetchSessionFile(settings: ServerSettings, sessionId: String, name: String): ByteArray =
     requestFromServer(settings, "/sessions/$sessionId/files/$name", readTimeoutMs = 30000) {
         it.inputStream.readBytes()
@@ -779,10 +744,9 @@ fun fetchSessionFile(settings: ServerSettings, sessionId: String, name: String):
 // One rate-limit window, rendered as a labeled bar on the usage screen.
 data class UsageWindow(
     /**
-     * The API's own word for which window this is -- "session" for the five-hour one.
+     * The API's own word for which window this is -- "session" for the five-hour one. The label
-     *
+     * beside it is written for a person to read, so matching on it would select nothing the day its
-     * How to find a particular window. The label beside it is written for a person to read, so
+     * wording changes.
-     * matching on it would select nothing the day its wording changes.
      */
     val kind: String,
     val label: String,
@@ -801,8 +765,8 @@ data class UsageSnapshot(
      * What came back: "ok", "notLoggedIn", "unreachable" or "failed".
      *
      * Four rather than a flag, because the screen has to treat them differently. "notLoggedIn" is a
-     * machine somebody chose not to put an account on -- a fact, not a fault -- while the other two
+     * machine somebody chose not to put an account on -- a fact, not a fault. Collapsing them made
-     * are faults worth chasing. Collapsing them made a healthy setup read as broken.
+     * a healthy setup read as broken.
      */
     val state: String,
     /** Why, for the two states that are faults. Absent otherwise. */
@@ -818,8 +782,8 @@ fun fetchUsage(settings: ServerSettings): List<UsageSnapshot> =
                 provider = snapshot.getString("provider"),
                 setup = snapshot.optString("setup"),
                 setupName = snapshot.optString("setupName"),
-                // Unknown to an older backend, and unknown is not "fine": defaulting to "ok"
+                // Unknown to an older backend, and unknown is not "fine": defaulting to "ok" would
-                // would draw an empty card as a healthy one.
+                // draw an empty card as a healthy one.
                 state = snapshot.optString("state").ifEmpty { "failed" },
                 detail = snapshot.optString("detail").ifEmpty { null },
                 windows =
@@ -840,8 +804,7 @@ fun fetchUsage(settings: ServerSettings): List<UsageSnapshot> =
  * Answers one question with everything that was chosen.
  *
  * A list even when one thing was picked, because that is the shape of the answer rather than a
- * special case of it. What a provider makes of several answers is its own business and is decided
+ * special case of it. What a provider makes of several answers is decided on the server.
- * on the server; nothing here joins, splits or reformats them for one.
  */
 fun answerQuestion(
     settings: ServerSettings,
@@ -868,9 +831,8 @@ fun interruptSession(settings: ServerSettings, sessionId: String) {
 /**
  * Ends the process behind a session, leaving the session and its transcript.
  *
- * Not a delete and not an interrupt: the conversation stays exactly where it is and [startSession]
+ * Not a delete and not an interrupt: the conversation stays where it is and [startSession] picks it
- * picks it back up. The server reports what it could not do -- there was nothing running, or the
+ * back up. The server reports what it could not do rather than answering the same way either way.
- * machine would not say whether there was -- rather than answering the same way either way.
  */
 fun stopSession(settings: ServerSettings, sessionId: String) {
     requestFromServer(settings, "/sessions/$sessionId/stop", method = "POST") {}
@@ -888,12 +850,10 @@ fun startSession(settings: ServerSettings, sessionId: String) {
  * caller confirms first; see ImportScreen.
  *
  * The work runs on the server, so this returning is not the same as it being done -- what says that
- * is each row's own state, through [fetchImportable] and the change stream. That is the point:
+ * is each row's own state. That is the point: leaving the screen used to cancel the delete.
- * leaving the screen used to cancel the delete it had started.
  *
- * One request for the whole batch, which is what makes a handover all-or-nothing. Sending one per
+ * One request for the whole batch, which is what makes a handover all-or-nothing. One per row meant
- * row meant a batch could half-arrive -- four deleted, two never asked for -- and the two that were
+ * a batch could half-arrive, and the rows that were missed looked exactly like rows not picked.
- * missed looked exactly like two that had not been picked.
  */
 fun deleteImportable(settings: ServerSettings, setup: String, sessionIds: List<String>) {
     requestFromServer(
@@ -910,8 +870,7 @@ fun deleteImportable(settings: ServerSettings, setup: String, sessionIds: List<S
  * Separate from [spawnSession] because the two are asked different questions. That one means "start
  * this and take me to it", so it waits and answers with the session. This is the import list's
  * batch: several at once, nobody waiting on any particular one, and the result arrives as a row
- * changing rather than as a reply -- which is what lets the screen be left. One request for all of
+ * changing -- which is what lets the screen be left.
- * them, for the reason [deleteImportable] gives.
  */
 fun startImport(
     settings: ServerSettings,
@@ -941,7 +900,7 @@ fun startImport(
  *
  * One request instead of one stream frame per event. The SSE stream is the right shape for live
  * events and the wrong one for a backlog: opening an imported session replayed hundreds of frames
- * before anything was readable, which looked exactly like the app loading top-down, because it was.
+ * before anything was readable, which looked exactly like the app loading top-down.
  *
  * [before] pages backwards for history somebody scrolls to; absent means the newest page.
  */
@@ -950,16 +909,14 @@ fun fetchTranscript(
     sessionId: String,
     before: Long? = null,
     limit: Int = 80,
-    // Count [limit] in rows, not events, joining a reply's streamed deltas into one -- so a page
+    // Count [limit] in rows, not events, joining a reply's streamed deltas into one -- so a page of
-    // of a delta-heavy conversation is a page of the screen rather than a fraction of one message.
+    // a delta-heavy conversation is a page of the screen rather than a fraction of one message. The
-    // The scroll-back pager wants this; the anchor restore does not (it counts events to a known
+    // scroll-back pager wants this; the anchor restore does not. Ignored by the server for the
-    // seq). Ignored by the server for the newest window, where the live cursor needs real seqs.
+    // newest window, where the live cursor needs real seqs.
-    // See the server's `read_window`.
     coalesce: Boolean = false,
-    // Return nothing at or below this seq, stopping the page here instead of at [limit]. The
+    // Return nothing at or below this seq, stopping the page here instead of at [limit]. The phone
-    // phone passes the end of the run it already holds cached, so a page never overlaps that copy
+    // passes the end of the run it already holds cached, so a page never overlaps that copy -- an
-    // -- an overlap it cannot store, since a coalesced event cannot be cut at a seq inside its own
+    // overlap it cannot store, since a coalesced event cannot be cut inside its own delta run.
-    // delta run. Exclusive, like the SSE route's cursor. See TranscriptCache and `read_window`.
     after: Long? = null,
 ): List<Pair<String, SeqEvent>> {
     val query = buildString {
@@ -970,9 +927,8 @@ fun fetchTranscript(
     }
     return requestFromServer(settings, "/sessions/$sessionId/transcript$query") { connection ->
         val body = JSONArray(connection.inputStream.bufferedReader().readText())
-        // The text as well as the event: the transcript cache stores the one and the fold needs
+        // The text as well as the event: the transcript cache stores the one and the fold needs the
-        // the other, and they have to be the same line -- a second entry point differing only in
+        // other, and they have to be the same line.
-        // return type would be two answers to one question.
         (0 until body.length()).map {
             val line = body.getJSONObject(it).toString()
             line to parseSeqEvent(line)
@@ -986,7 +942,7 @@ fun fetchTranscript(
  * The name is the backend's own -- it is what the list shows and it exists before any process does
  * -- so this settles it rather than asking. Where the thing running the session has a name of its
  * own, the backend passes it on, which is what makes a session the same session in Claude Code's
- * picker and to any other agent that lists it.
+ * picker.
  */
 fun renameSession(settings: ServerSettings, sessionId: String, title: String) {
     requestFromServer(
@@ -1078,10 +1034,9 @@ fun deleteSession(settings: ServerSettings, sessionId: String, deleteForeign: Bo
     requestFromServer(settings, "/sessions/$sessionId$query", method = "DELETE") {}
 }
 
-// Models: what this backend has downloaded, what it is downloading, and
+// Models: what this backend has downloaded, what it is downloading, and what HuggingFace offers.
-// what HuggingFace offers. Browsing is proxied by the server rather than
+// Browsing is proxied by the server rather than done here, because this app trusts exactly one
-// done here, because this app trusts exactly one certificate and has no
+// certificate and has no general internet trust to spend on huggingface.co.
-// general internet trust to spend on huggingface.co.
 
 data class LocalModel(val key: String, val repo: String, val file: String, val bytes: Long)
 

app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt

@@ -29,11 +29,9 @@ import kotlinx.coroutines.withContext
  * One `when` rather than a navigation library: a handful of screens, with [Screen.Main] as the root
  * and the back button the only other way between them.
  *
- * Import, models and setups are not here any more. They are tabs inside [MainScreen] -- four views
+ * Import, models and setups are tabs inside [MainScreen] -- four views of the same backend, none of
- * of the same backend, none of them a step down from another -- and what is left in this `when` is
+ * them a step down from another -- and what is left here is only what genuinely is a step down: one
- * only what genuinely is a step down: one session, spawning one, and settings. A session's own
+ * session, spawning one, and settings.
- * settings are not among them: they are a dialog over the session, which is where the thing they
- * change is.
  */
 private sealed class Screen {
     data object Main : Screen()
@@ -43,10 +41,8 @@ private sealed class Screen {
      *
      * The explorer is a layer on this screen rather than a screen of its own, so the session under
      * it stays composed: its event stream keeps flowing, its scroll position and draft stay put,
-     * and coming back from a file costs nothing. As a sibling `Screen` it would be disposed and
+     * and coming back from a file costs nothing. As a sibling `Screen` it would be disposed and re-
-     * re-created on every return, refetching the transcript over the tunnel -- which is exactly the
+     * created on every return, refetching the transcript over the tunnel.
-     * flip between "what did it change" and "what is it saying" that this feature exists for. The
-     * image viewer already made the same choice for the same reason.
      */
     data class Session(val summary: SessionSummary, val files: FilesTarget? = null) : Screen()
 
@@ -60,7 +56,7 @@ private sealed class Screen {
  *
  * The notification names an id and nothing else, so opening it means fetching the session first.
  * [serial] tells two taps on the same session's notification apart, since they are two requests and
- * would otherwise compare equal -- see MainActivity, which counts them.
+ * would otherwise compare equal.
  */
 data class SessionOpenRequest(val sessionId: String, val serial: Int)
 
@@ -68,8 +64,8 @@ data class SessionOpenRequest(val sessionId: String, val serial: Int)
 private data class FailedOpen(val request: SessionOpenRequest, val message: String)
 
 /**
- * [settingsVersion] bumps when enrollment lands via an `aiapp://` intent (see MainActivity),
+ * [settingsVersion] bumps when enrollment lands via an `aiapp://` intent (see MainActivity), re-
- * re-reading the stored settings -- a plain `remember` would keep serving the pre-enrollment null.
+ * reading the stored settings -- a plain `remember` would keep serving the pre-enrollment null.
  *
  * [openRequest] is the session a notification tap asked for, likewise from MainActivity.
  *
@@ -89,8 +85,8 @@ fun AppRoot(
     // A notification tap this could not follow, and why. Null both before one is asked for and
     // after one succeeds, since success is a screen rather than a message.
     var failedOpen by remember { mutableStateOf<FailedOpen?>(null) }
-    // Bumped whenever another screen changes something the list shows, so
+    // Bumped whenever another screen changes something the list shows, so returning to it
-    // returning to it refetches instead of showing a stale list.
+    // refetches.
     var reloadToken by remember { mutableIntStateOf(0) }
     // Cleared by the session screen that attached it, not when a newer request arrives: a share
     // must be attached exactly once, and only the screen that did it knows that it has.
@@ -104,9 +100,8 @@ fun AppRoot(
         }
     }
 
-    // A standing condition rather than a per-request failure, so it is
+    // A standing condition rather than a per-request failure, so it is stated once here instead of
-    // stated once here instead of appended to every error that might be
+    // appended to every error it might cause. Without this the app is simply unreachable and every
-    // caused by it. Without this the app is simply unreachable and every
     // screen blames the server or the tunnel for it.
     if (!localNetworkAllowed(context)) {
         Text(
@@ -121,8 +116,8 @@ fun AppRoot(
 
     val current = settings
     if (current == null) {
-        // Not enrolled yet: settings is the only usable screen. The QR
+        // Not enrolled yet: settings is the only usable screen. The QR path lands in MainActivity
-        // path lands in MainActivity and recomposes from the top.
+        // and recomposes from the top.
         Box(Modifier.imePadding()) {
             SettingsScreen(
                 existing = null,
@@ -136,10 +131,9 @@ fun AppRoot(
         return
     }
 
-    // The one way back, whichever screen is showing and whether it was
+    // The one way back, whichever screen is showing and whether it was reached by the system back
-    // reached by the system back gesture or a screen's own Back button.
+    // gesture or a screen's own Back button. Every leaf screen can have changed something the list
-    // Every leaf screen can have changed something the list shows, so it
+    // shows, so it always refetches.
-    // always refetches.
     val goToMain = {
         reloadToken++
         screen = Screen.Main
@@ -149,8 +143,8 @@ fun AppRoot(
     }
 
     // Turning a notification into the screen it points at. The id has to be resolved to a session
-    // first, because that is what SessionScreen is given -- and unlike a list row, which is a
+    // first, because that is what SessionScreen is given -- and unlike a list row, there is nothing
-    // snapshot the list already fetched, there is nothing here to seed it from.
+    // here to seed it from.
     //
     // A failure is reported rather than swallowed: somebody deliberately tapped a notification, so
     // an app that opens to the session list with no explanation looks like the tap missed.
@@ -180,10 +174,9 @@ fun AppRoot(
         )
     }
 
-    // Every screen but the session takes the keyboard as bottom padding here. The session
+    // Every screen but the session takes the keyboard as bottom padding here. The session screen
-    // screen deliberately does not: resizing a whole screen on every frame of the keyboard
+    // deliberately does not: resizing a whole screen on every frame of the keyboard animation is
-    // animation is the cost that made it lag, so it moves only its composer and transcript --
+    // the cost that made it lag, so it moves only its composer and transcript.
-    // see the layout note in SessionScreen.
     when (val here = screen) {
         is Screen.Main ->
             Box(Modifier.imePadding()) {
@@ -202,15 +195,14 @@ fun AppRoot(
             }
         is Screen.Session ->
             // Keyed on the id, because a different session is a different screen rather than this
-            // one showing other rows. SessionScreen remembers a transcript, an open event stream, a
+            // one showing other rows. SessionScreen remembers a transcript, an open stream, a draft
-            // draft and a scroll position, and without the key Compose keeps all of it across the
+            // and a scroll position, and without the key Compose keeps all of it across the change
-            // change and merges two conversations -- which crashes the list on the first duplicate
+            // and merges two conversations -- which crashes the list on the first duplicate row
-            // row key. Only reachable since a notification can move straight from one session to
+            // key. Only reachable since a notification can move straight from one session to
-            // another; every other way here passes through [Screen.Main], which disposes it anyway.
+            // another.
             key(here.summary.id) {
-                // A Box so the explorer can be drawn *over* the session rather than instead of
+                // A Box so the explorer can be drawn *over* the session rather than instead of it.
-                // it; the session stays composed underneath. No imePadding here, for the reason
+                // No imePadding here, for the reason above -- the explorer adds its own.
-                // above -- the explorer adds its own, since it has a text field.
                 Box {
                     SessionScreen(
                         settings = current,
@@ -257,8 +249,7 @@ fun AppRoot(
 
     // Last, so it draws over the screen above rather than under it: these are stacked in the Box
     // the activity puts around this, and that Box paints in the order it was given. A session
-    // wanting attention is not a fact about the page somebody happens to be on, so it is not the
+    // wanting attention is not a fact about the page somebody happens to be on. Tapping one is the
-    // page's job to leave room for it. Tapping one is the same act as tapping a notification, so
+    // same act as tapping a notification, so it goes through the same `open`.
-    // it goes through the same `open`, failure dialog included.
     SessionAlerts(onOpen = { request -> scope.launch { open(request) } })
 }

app/androidApp/src/main/kotlin/com/example/aiapp/AskQuestion.kt

@@ -41,13 +41,12 @@ data class QuestionAnswer(val questionId: String, val answers: List<String>)
  * What the reader has settled on for one question, before any of it is sent.
  *
  * Held here rather than inferred from the transcript, which is what made picking an option feel
- * broken: the mark used to appear only when the answer had crossed the tunnel, been recorded and
+ * broken: the mark used to appear only when the answer had crossed the tunnel and come back as an
- * come back as an event, so on a phone the card sat unchanged for most of a second after a tap and
+ * event, so the card sat unchanged for most of a second after a tap.
- * the natural response was to tap again.
  *
  * Picked options and typed words are one field each because they are alternatives rather than
- * parts: answering in the reader's own words is the case no option covers, so typing puts the picks
+ * parts: typing puts the picks away and picking puts the words away, so there is never a draft that
- * away and picking puts the words away, and there is never a draft that means two things.
+ * means two things.
  */
 data class Draft(val picked: Set<String> = emptySet(), val other: String = "") {
     val settled: Boolean
@@ -65,29 +64,26 @@ data class Draft(val picked: Set<String> = emptySet(), val other: String = "") {
 /**
  * Every question one tool call is waiting on, one at a time.
  *
- * All of it comes from the question events themselves -- what each option means, what picking it
+ * All of it comes from the question events themselves. None of it is read out of the call's own
- * would produce, whether several may be picked at once. None of it is read out of the call's own
  * input, which is one provider's JSON: parsing that here would put that provider's schema in the
  * app, where no other provider can reach it and where it drifts the first time the schema moves.
  *
  * One question on screen with arrows to the others, rather than all of them stacked. A card asking
  * three questions with four options and a description each is several screens tall, so the reader
- * scrolls past the question they are answering to reach the button that sends it, and never sees
+ * scrolls past the question they are answering to reach the button that sends it. Paged, each
- * the whole of any one of them. Paged, each question is a screen and the count says how many are
+ * question is a screen and the count says how many are left.
- * left -- which is also what makes "not all of them are answered" something the reader can act on
- * rather than something to go hunting for.
  *
  * Nothing is sent until Submit. Answering is one act even when it is several questions: the tool
- * asked them together and is waiting on all of them, and sending each as it was tapped meant the
+ * asked them together, and sending each as it was tapped meant the reader could not change their
- * reader could not change their mind about the first after reading the third.
+ * mind about the first after reading the third.
  */
 @Composable
 fun AskUserQuestionBody(
     asks: List<TranscriptItem.QuestionCard>,
     onAnswer: (List<QuestionAnswer>, onSettled: () -> Unit) -> Unit,
 ) {
-    // Seeded from what was already answered, so a card the reader comes back to shows their
+    // Seeded from what was already answered, so a card the reader comes back to shows their answers
-    // answers rather than an empty draft over them.
+    // rather than an empty draft over them.
     var drafts by
         remember(asks.map { it.id }) {
             mutableStateOf(
@@ -125,7 +121,7 @@ fun AskUserQuestionBody(
                     modifier = Modifier.weight(1f),
                 )
                 // Disabled at the ends rather than absent, so the pair keeps its place and the
-                // reader can see that there is nothing further that way.
+                // reader can see there is nothing further that way.
                 MarkButton("Previous question", { at-- }, enabled = at > 0) {
                     Chevron(Pointing.Left, colour = LocalContentColor.current)
                 }
@@ -143,7 +139,7 @@ fun AskUserQuestionBody(
         if (outstanding.isNotEmpty()) {
             Spacer(Modifier.height(12.dp))
             // Greyed until every question has an answer, because the tool is waiting on all of
-            // them: a submit that sent two of three would leave the third one asked and the card
+            // them: a submit that sent two of three would leave the third asked and the card
             // looking dealt with.
             val ready = outstanding.all { drafts[it.id]?.settled == true }
             Button(
@@ -155,8 +151,8 @@ fun AskUserQuestionBody(
                         }
                     ) {
                         // Back to a button whatever happened. A refusal is reported by the screen
-                        // around this, and the draft is still here to send again -- a spinner
+                        // around this, and the draft is still here to send again -- a spinner that
-                        // that never stops would be the only sign of a failure this card cannot
+                        // never stops would be the only sign of a failure this card cannot
                         // describe.
                         sending = false
                     }
@@ -165,8 +161,8 @@ fun AskUserQuestionBody(
                 modifier = Modifier.fillMaxWidth(),
             ) {
                 if (sending) {
-                    // In the button rather than beside it, so the row does not change height at
+                    // In the button rather than beside it, so the row does not change height at the
-                    // the moment it is pressed.
+                    // moment it is pressed.
                     CircularProgressIndicator(
                         Modifier.height(18.dp).width(18.dp),
                         strokeWidth = 2.dp,
@@ -186,8 +182,7 @@ fun AskUserQuestionBody(
  * One question: what is being asked, what can be answered, and what was.
  *
  * The same body wherever a question appears -- on the call that asked it, or as a card of its own
- * when nothing did. A question is the same thing either way, and two renderings of it would be two
+ * when nothing did. Two renderings of it would be two places for an answer to go missing.
- * places for an answer to go missing.
  *
  * [draft] is what the reader has picked so far and [onDraft] is how they change it; nothing here
  * sends anything. An answered question ignores both and draws what was answered.
@@ -214,10 +209,10 @@ fun AskedQuestion(
         // replacing them with a line repeating it. The options are what the question *was*, and
         // dropping them leaves an answer with nothing to have been an answer to -- "Sonnet" says
         // very little without the three it was chosen over. Marked in the same purple that says
-        // "picked" while the question is still open, so it is one appearance learned once.
+        // "picked" while the question is open, so it is one appearance learned once.
         val answered = ask.answers.isNotEmpty()
-        // What is marked: what was answered once there is an answer, and what the finger has
+        // What is marked: what was answered once there is an answer, and what the finger has chosen
-        // chosen until then.
+        // until then.
         val marked = if (answered) ask.answers.toSet() else draft.picked
         // Null once the question is answered: the options stay and stop being pressable.
         val onPick: ((String) -> Unit)? =
@@ -233,9 +228,9 @@ fun AskedQuestion(
                 }
             }
         }
-        // What was answered in the reader's own words, which no option can mark -- see
+        // What was answered in the reader's own words, which no option can mark. Only ever the
-        // [OtherAnswer]. Only ever the answers that match nothing offered, so a question answered
+        // answers that match nothing offered, so a question answered by picking says it by the
-        // by picking says it by the mark alone.
+        // mark.
         val inWords = ask.answers.filterNot { answer -> ask.options.any { it.label == answer } }
         if (inWords.isNotEmpty()) {
             Text(
@@ -252,10 +247,8 @@ fun AskedQuestion(
 }
 
 /**
- * [label] added to, or taken out of, what [draft] has picked.
+ * [label] added to, or taken out of, what [draft] has picked. A single-answer question replaces
- *
+ * rather than accumulates, and either way picking puts any typed words away -- see [Draft].
- * A single-answer question replaces rather than accumulates, and either way picking puts any typed
- * words away -- see [Draft].
  */
 private fun pick(draft: Draft, label: String, multiSelect: Boolean): Draft =
     when {
@@ -269,8 +262,7 @@ private fun pick(draft: Draft, label: String, multiSelect: Boolean): Draft =
  *
  * Outlined rather than tinted. Drawn first as a card one step up the surface ladder, it was
  * indistinguishable from the card behind it -- three paragraphs of text where three things to press
- * should have been, which is the failure a tint step routinely produces on a dark theme. A border
+ * should have been. A border is one cue and it is unambiguous.
- * is one cue and it is unambiguous.
  */
 @Composable
 private fun OptionCard(option: QuestionOption, selected: Boolean, onPick: () -> Unit) {
@@ -324,8 +316,8 @@ private fun Preview(preview: String) {
             preview,
             style = MaterialTheme.typography.bodySmall,
             fontFamily = FontFamily.Monospace,
-            // Not wrapped: these are mockups and diffs, where a wrapped line reads as two lines
+            // Not wrapped: these are mockups and diffs, where a wrapped line reads as two lines of
-            // of the thing being previewed.
+            // the thing being previewed.
             softWrap = false,
             modifier = Modifier.padding(8.dp).horizontalScroll(rememberScrollState()),
         )
@@ -336,8 +328,7 @@ private fun Preview(preview: String) {
  * The choice the asker always leaves open, and the app has to as well.
  *
  * Every AskUserQuestion carries an implicit "Other" -- the reader may answer in their own words
- * rather than pick. Leaving it out narrows a question that was never that narrow, and the reader
+ * rather than pick. Leaving it out narrows a question that was never that narrow.
- * cannot tell that it was ever open.
  */
 @Composable
 private fun OtherAnswer(text: String, onText: (String) -> Unit) {
@@ -358,8 +349,7 @@ private fun OtherAnswer(text: String, onText: (String) -> Unit) {
  *
  * A Row hands out intrinsic widths in order and clips whatever runs past the edge, so a question
  * with four options showed the first one or two and dropped the rest off the side of the screen.
- * That does not read as a bug: it reads as those having been the only choices, which is the worst
+ * That reads as those having been the only choices.
- * way for a list of choices to be wrong.
  */
 @Composable
 fun AnswerOptions(
@@ -379,8 +369,8 @@ fun AnswerOptions(
             OutlinedButton(
                 onClick = { onPick?.invoke(option.label) },
                 // Disabled rather than removed, so an answered question still shows what it
-                // offered. Material dims a disabled button's own border and label, which would
+                // offered. Material dims a disabled button's own border and label, which would take
-                // take the mark with it -- both are stated here instead.
+                // the mark with it -- both are stated here instead.
                 enabled = onPick != null,
                 border =
                     BorderStroke(

app/androidApp/src/main/kotlin/com/example/aiapp/Attachment.kt

@@ -28,8 +28,8 @@ fun attachmentName(ref: String): String = ref.substringAfter('-', ref)
 
 /**
  * One attachment on a sent message, drawn as what it is: an image inline, a file as its name. A
- * file is not fetched -- there is nothing on this phone to open a trace or a log with -- so the
+ * file is not fetched -- there is nothing on this phone to open a trace with -- so the name is all
- * name is the whole of it.
+ * of it.
  */
 @Composable
 fun Attachment(
@@ -50,8 +50,7 @@ fun Attachment(
 
 /**
  * A file's name, one line, in the face names are read in. Overlong names lose their middle: a name
- * is identified by both ends -- what it is at the front, what kind at the back -- and either
+ * is identified by both ends -- what it is at the front, what kind at the back.
- * ellipsis alone takes away one of them.
  */
 @Composable
 fun FileName(name: String, modifier: Modifier = Modifier) {

app/androidApp/src/main/kotlin/com/example/aiapp/Attachments.kt

@@ -20,10 +20,8 @@ import kotlin.math.max
  * to be either thrown away or rejected -- which is what "sending an image is broken" was.
  *
  * Shrunk here rather than on the backend, so the bytes that never mattered are never sent: the
- * expensive part of this on a phone is the upload, not the decode. What the limit *is* comes from
+ * expensive part on a phone is the upload, not the decode. What the limit *is* comes from the
- * the server, per session -- see `DriverKind::max_image_edge` -- because that is where a provider's
+ * server, per session, because that is where a provider's requirements are known.
- * requirements are known, and a phone that carried its own copy of them would be a second place to
- * update when one changes.
  */
 suspend fun uploadPickedImage(
     context: Context,
@@ -53,17 +51,16 @@ suspend fun uploadPicked(
     if (mime != null && mime.startsWith("image/")) {
         return uploadPickedImage(context, settings, sessionId, uri, maxEdge)
     }
-    // Opened before the request starts, so a provider that refuses says so here and not from
+    // Opened before the request starts, so a provider that refuses says so here and not from inside
-    // inside the connection; then streamed, since a trace or a log is bigger than this process
+    // the connection; then streamed, since a trace is bigger than this process should hold at once.
-    // should hold at once.
     val source = openSource(resolver, uri)
     val name = displayName(resolver, uri)
     return uploadAttachment(settings, sessionId, mime ?: "application/octet-stream", name) { out ->
         try {
             source.use { it.copyTo(out, COPY_BUFFER) }
         } catch (e: java.io.IOException) {
-            // Either side of the copy can fail; the message names the file, which is the
+            // Either side of the copy can fail; the message names the file, which is the part the
-            // part the reader can do something about.
+            // reader can do something about.
             throw ApiException("couldn't send $name: ${e.message}", cause = e)
         }
     }
@@ -76,7 +73,7 @@ private const val COPY_BUFFER = 64 * 1024
  *
  * A share arrives with whatever access the other app granted, and a provider that refuses says so
  * with a `SecurityException`; a file gone between the pick and the read is an `IOException`. Both
- * are things the reader can act on, so neither is left to end the process.
+ * are things the reader can act on.
  */
 private fun openSource(resolver: ContentResolver, uri: Uri): java.io.InputStream =
     try {
@@ -110,9 +107,9 @@ private fun displayName(resolver: ContentResolver, uri: Uri): String {
 /**
  * The bytes to upload and what they are, scaled down only if they need to be.
  *
- * An image already inside the limit is uploaded exactly as it came, rather than decoded and
+ * An image already inside the limit is uploaded exactly as it came, rather than decoded and re-
- * re-encoded to the same size: a round trip through JPEG loses a little every time, and there is
+ * encoded to the same size: a round trip through JPEG loses a little every time. This is also the
- * nothing to gain from it. This is also the path a provider with no limit always takes.
+ * path a provider with no limit always takes.
  */
 private fun readForUpload(context: Context, uri: Uri, maxEdge: Int?): Pair<ByteArray, String> {
     val resolver = context.contentResolver
@@ -128,9 +125,9 @@ private fun readForUpload(context: Context, uri: Uri, maxEdge: Int?): Pair<ByteA
     // decision it has no business making.
     if (longest <= 0 || longest <= maxEdge) return original to mime
 
-    // Powers of two first, which is all the decoder can do, and then the exact scale. Decoding
+    // Powers of two first, which is all the decoder can do, and then the exact scale. Decoding the
-    // the full twelve megapixels only to shrink it is how this runs out of memory on the images
+    // full twelve megapixels only to shrink it is how this runs out of memory on the images it most
-    // it most needs to handle.
+    // needs to handle.
     val decode =
         BitmapFactory.Options().apply {
             inSampleSize = Integer.highestOneBit(max(1, longest / maxEdge))
@@ -141,9 +138,8 @@ private fun readForUpload(context: Context, uri: Uri, maxEdge: Int?): Pair<ByteA
     val matrix = Matrix()
     if (scale < 1f) matrix.postScale(scale, scale)
     // The camera writes which way up the picture is into EXIF rather than rotating the pixels, and
-    // re-encoding drops the tag -- so a portrait photo would arrive at the model on its side, with
+    // re-encoding drops the tag -- so a portrait photo would arrive at the model on its side.
-    // nothing anywhere saying so. Applied to the same matrix as the scale, so it costs no second
+    // Applied to the same matrix as the scale, so it costs no second copy of the bitmap.
-    // copy of the bitmap.
     matrix.postRotate(exifRotation(original))
     val scaled = Bitmap.createBitmap(decoded, 0, 0, decoded.width, decoded.height, matrix, true)
     val out = ByteArrayOutputStream()
@@ -166,8 +162,8 @@ private fun exifRotation(bytes: ByteArray): Float =
             else -> 0f
         }
     } catch (_: java.io.IOException) {
-        // No EXIF, or none this can read. Upright is the assumption every
+        // No EXIF, or none this can read. Upright is the assumption every image without the tag is
-        // image without the tag is displayed under anyway.
+        // displayed under anyway.
         0f
     }
 

app/androidApp/src/main/kotlin/com/example/aiapp/Bubble.kt

@@ -8,18 +8,16 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Shape
 import androidx.compose.ui.unit.dp
 
-// The composer's row of settings and pickers, and the menus they open. One file because the
+// The composer's row of settings and pickers, and the menus they open. One file because the outline
-// outline and the corner are one appearance: a control shaped like this opens a surface shaped
+// and the corner are one appearance: a control shaped like this opens a surface shaped like this.
-// like this, and a reader learns the pair once.
 
 /**
  * A bordered pill: a control that can be seen without being pressed.
  *
  * The composer's row -- attach, model, permission mode -- was text buttons, which draw nothing at
- * all until they are touched. Three bare words sitting under the message field read as a caption
+ * all until they are touched. Three bare words under the message field read as a caption about the
- * about the field rather than as three things to press, and the only way to find out otherwise was
+ * field rather than as three things to press. The outline says "control" without the weight of a
- * to press one. The outline says "control" without the weight of a filled button, which is reserved
+ * filled button, which is reserved for the two that act on the session.
- * here for the two that act on the session (send, and start/stop).
  */
 @Composable
 fun BubbleButton(
@@ -32,8 +30,8 @@ fun BubbleButton(
         onClick = onClick,
         enabled = enabled,
         shape = BubbleShape,
-        // A text button's padding rather than a filled button's 24dp: these sit three across
+        // A text button's padding rather than a filled button's 24dp: these sit three across under
-        // under the message field, and the wider padding is what decides whether the row fits.
+        // the message field, and the wider padding is what decides whether the row fits.
         contentPadding = ButtonDefaults.TextButtonContentPadding,
         modifier = modifier,
     ) {
@@ -48,7 +46,6 @@ val BubbleShape: Shape = RoundedCornerShape(percent = 50)
  * The corner on a menu one of these opens.
  *
  * A radius rather than [BubbleShape]'s half-height: a menu is as tall as its options, and rounding
- * ends that tall would bow its sides. This is the roundest corner that still leaves a straight edge
+ * ends that tall would bow its sides.
- * beside a one-line option, which is the shortest menu here.
  */
 val BubbleMenuShape: Shape = RoundedCornerShape(20.dp)

app/androidApp/src/main/kotlin/com/example/aiapp/BusyItem.kt

@@ -26,20 +26,16 @@ import androidx.compose.ui.unit.dp
  * of the operation over it.
  *
  * One composable rather than a pattern each list repeats, because "this row is busy" has to look
- * the same in the import list and the session list or the appearance becomes a per-screen dialect
+ * the same in the import list and the session list or the appearance becomes a per-screen dialect.
- * rather than something the reader learns once.
  *
  * [label] names the operation and `null` means none is running. One parameter rather than a boolean
- * beside a string, which can disagree: there is no such thing as busy with nothing happening. It is
+ * beside a string, which can disagree. It is a *word* because a spinner alone cannot say which
- * a *word* because a spinner alone cannot say which operation this is — deleting and importing are
+ * operation this is -- deleting and importing are different in kind.
- * different in kind, and losing a session to the wrong one is not recoverable by waiting.
  *
  * It does **not** make the row inert; the caller disables its own click handling while it passes a
- * label. That was the other way round at first — an overlay consuming pointer events, so no caller
+ * label. That was the other way round at first -- an overlay consuming pointer events -- and it
- * had to remember — and it swallowed the drag along with the tap, which meant a list could not be
+ * swallowed the drag along with the tap, so a list could not be scrolled while anything in it was
- * scrolled while anything in it was busy. Consuming taps but not drags means re-deciding what a
+ * busy.
- * gesture is above the components that already decide it; disabling the click is the platform's own
- * answer and leaves the scroll where it belongs.
  */
 @Composable
 fun BusyItem(label: String?, content: @Composable () -> Unit) {
@@ -71,14 +67,12 @@ fun BusyItem(label: String?, content: @Composable () -> Unit) {
 /**
  * How an item looks while it is being acted on: darker, and nearly grey.
  *
- * Both, rather than either alone. Dimming by itself is what this app already used for a row on its
+ * Both, rather than either alone. Dimming by itself is the same cue as a disabled control, so a
- * way out, and it is the same cue as a disabled control, so a busy row read as one more thing that
+ * busy row read as one more thing that could not be tapped. Draining the colour is what says the
- * could not be tapped. Draining the colour is what says the row is *suspended* — the status word,
+ * row is *suspended* -- the status word and everything else that means something by its colour stop
- * the accent on a warning and everything else that means something by its colour stop meaning it
+ * meaning it for as long as the operation runs, which is exactly true.
- * for as long as the operation runs, which is exactly true: none of them is being kept up to date.
  *
- * Not all the way to grey. A row with no colour left is hard to find again in a list, and the
+ * Not all the way to grey: a row with no colour left is hard to find again in a list.
- * reader is watching this one.
  */
 private fun Modifier.busy(busy: Boolean): Modifier =
     if (!busy) this

app/androidApp/src/main/kotlin/com/example/aiapp/Chevron.kt

@@ -27,13 +27,10 @@ enum class Pointing {
  *
  * One composable for all four directions rather than one per axis that differ by which coordinate
  * gets the minus sign -- the copies would drift, and the drift would be a bug in exactly one
- * direction. The shape is written once in its own coordinates, where x runs across the opening and
+ * direction. The shape is written once in its own coordinates, and [Pointing] is only a table of
- * y runs from the open side to the tip, and [Pointing] is only a table of how those two map onto
+ * how those map onto the box.
- * the box.
  *
- * It draws no label of its own, so every caller owes it a `contentDescription`: this is the whole
+ * It draws no label of its own, so every caller owes it a `contentDescription`.
- * of what assistive technology has to go on, and it is also the answer to "what was that arrow for"
- * six months from now.
  */
 @Composable
 fun Chevron(

app/androidApp/src/main/kotlin/com/example/aiapp/CodeFence.kt

@@ -30,14 +30,12 @@ import org.intellij.markdown.ast.getTextInNode
  * sits on, scrolling sideways rather than wrapping.
  *
  * The renderer's own fence drew the same block in plain text. The scanner that colours a tool
- * call's command colours a reply's code the same way, through [highlighted] and one palette, so a
+ * call's command colours a reply's code the same way, so a `kotlin` fence and the Kotlin a tool
- * `kotlin` fence and the Kotlin a tool wrote are the same colours. A fence in a language [scan] has
+ * wrote are the same colours. A fence in a language [scan] has no rules for is plain rather than
- * no rules for is plain rather than wrongly coloured: [fenceLanguage] answers null for those, and
+ * wrongly coloured.
- * plain is what the reader would have seen before.
  *
  * Finding the code is still the library's: which children of the node are the fence markers, the
- * language word and the code between them is its knowledge of the parser, and [MarkdownCodeFence]
+ * language word and the code between them is its knowledge of the parser.
- * hands out the code and the language and leaves the drawing to the block it is given.
  */
 @Composable
 fun CodeFence(
@@ -67,14 +65,12 @@ fun CodeBlock(
 /**
  * The code inside a fence or indented block, and the highlighter's language for its info word.
  *
- * Which children of the node are the fence markers, the language word and the code between them is
+ * Copied from the library's `MarkdownCodeFence` rather than called: that one is a composable, and
- * the library's knowledge of the parser, copied from its `MarkdownCodeFence` rather than called:
+ * the whole point here is that [warm] can run this on a background thread and highlight the same
- * that one is a composable, and the whole point of this function is that [warm] can run it on a
+ * string the drawing will ask for. Two extractions would be two keys, and the warmed answer would
- * background thread and highlight the same string the drawing will ask for. Two extractions would
+ * be silently missed at every fence.
- * be two keys, and the warmed answer would be silently missed at every fence.
  *
- * Null for a fence too short to hold anything -- an unterminated one still arriving, which the
+ * Null for a fence too short to hold anything -- an unterminated one still arriving.
- * library skips as invalid.
  */
 fun fenceContent(content: String, node: ASTNode): Pair<String, Language?>? {
     val word =
@@ -97,7 +93,6 @@ fun fenceContent(content: String, node: ASTNode): Pair<String, Language?>? {
  *
  * The renderer's own block, less what nothing here needs: the same background, corner, padding and
  * sideways scroll, without the shadow, the border and the empty pointer handler it also carried.
- * The vertical margin is the renderer's too, kept so a reply's fences sit where they always have.
  */
 @Composable
 private fun CodeBlockText(
@@ -117,8 +112,7 @@ private fun CodeBlockText(
             .semantics { isTraversalGroup = true }
     ) {
         BasicText(
-            // No language while the block is still being written, which is what draws it plain;
+            // No language while the block is still being written, which is what draws it plain.
-            // see [MarkdownRoot]'s `streaming`.
             replies.highlighted(code, language.takeUnless { streaming }),
             style = style,
             modifier = Modifier.horizontalScroll(rememberScrollState()).padding(padding.codeBlock),
@@ -141,14 +135,12 @@ fun fenceLanguage(name: String?): Language? =
  * The highlighter's language for a *file*, from its name.
  *
  * The same table [fenceLanguage] reads, deliberately: it already keys on the extensions people
- * write after the backticks -- `kt`, `rs`, `py` -- because the extension is as often what gets
+ * write after the backticks. One table rather than two, so a language added for fences is a
- * written there as the language's name. One table rather than two, so a language added for fences
+ * language added for files and neither can be the one somebody forgot.
- * is a language added for files and neither can be the one somebody forgot.
  *
- * The extension is the part after the *last* dot, which is what makes `build.gradle.kts` Kotlin and
+ * The extension is the part after the *last* dot, which is what makes `build.gradle.kts` Kotlin. A
- * `Cargo.toml` TOML. A leading dot is not one: `.bashrc` has no extension, it has a name that
+ * leading dot is not one: `.bashrc` has no extension, it has a name that starts with a dot. A name
- * starts with a dot, and reading `bashrc` as an extension would look up a word no table has. A name
+ * with no dot at all -- `Makefile` -- is likewise null, and null is drawn plain.
- * with no dot at all -- `Makefile`, `LICENSE` -- is likewise null, and null is drawn plain.
  */
 fun fileLanguage(name: String): Language? {
     val dot = name.lastIndexOf('.')
@@ -206,10 +198,9 @@ private val FENCE_LANGUAGES: Map<String, Language> =
     )
 
 /**
- * Every fence in [parse], as the code and language [highlight] will be asked for.
+ * Every fence in [parse], as the code and language [highlight] will be asked for. Walks the whole
- *
+ * tree rather than the top level: a fence inside a list item or a quote is drawn the same way and
- * Walks the whole tree rather than the top level: a fence inside a list item or a quote is drawn
+ * costs the same to lex.
- * the same way and costs the same to lex.
  */
 fun fences(parse: State): List<Pair<String, Language?>> {
     val success = parse as? State.Success ?: return emptyList()

app/androidApp/src/main/kotlin/com/example/aiapp/Commands.kt

@@ -25,8 +25,7 @@ import androidx.compose.ui.unit.dp
  * These are the two this app understands, and understanding them is what lets it show them: a
  * suggestion while one is being typed, a name in the settings screen that sends one, and a bubble
  * that stays up while the session is too busy to run it. Anything else beginning with "/" is passed
- * through to whatever runs the session, because a dialect's own vocabulary is its own and grows
+ * through, because a dialect's own vocabulary grows without this list.
- * without this list -- it just arrives unannounced and unexplained.
  */
 data class SessionCommand(
     /** With the slash, as it is typed and as it is sent. */
@@ -90,8 +89,8 @@ fun CommandSuggestions(
                     verticalAlignment = Alignment.CenterVertically,
                 ) {
                     Text(
-                        // The command in the colour commands are, so the suggestion and the
+                        // The command in the colour commands are, so the suggestion and the bubble
-                        // bubble it becomes are visibly the same thing.
+                        // it becomes are visibly the same thing.
                         if (command.argument == null) command.name
                         else "${command.name} <${command.argument}>",
                         style = MaterialTheme.typography.titleSmall,
@@ -117,8 +116,7 @@ fun CommandSuggestions(
  * anything appearing here.
  *
  * [waiting] is a command the session is too busy to run yet, which is a state with a spinner and a
- * reason: pressing Compact in the middle of a long turn otherwise does nothing visible for minutes
+ * reason: pressing Compact in the middle of a long turn otherwise does nothing visible for minutes.
- * and reads as having been missed.
  */
 @Composable
 fun CommandBubble(text: String, waiting: Boolean = false) {
@@ -128,8 +126,8 @@ fun CommandBubble(text: String, waiting: Boolean = false) {
             modifier = Modifier.align(Alignment.CenterEnd).padding(start = 48.dp),
         ) {
             Column(Modifier.padding(12.dp)) {
-                // Stated beside the fill rather than inherited: a semantic colour has to carry
+                // Stated beside the fill rather than inherited: a semantic colour has to carry its
-                // its own contrast, because the surface under it will not change to rescue it.
+                // own contrast, because the surface under it will not change to rescue it.
                 Text(text, color = MaterialTheme.colorScheme.inverseOnSurface)
                 if (waiting) {
                     Spacer(Modifier.height(6.dp))

app/androidApp/src/main/kotlin/com/example/aiapp/Compaction.kt

@@ -7,12 +7,10 @@ import androidx.compose.ui.Modifier
  * The mark a compaction leaves in the transcript.
  *
  * A divider rather than something anybody said: everything above it is out of the session's context
- * now, and that is a fact about the conversation, not a turn in it. It has no collapsed form -- it
+ * now, and that is a fact about the conversation, not a turn in it. Drawn by [TranscriptDivider],
- * is already one line, and there is nothing behind it to open. Drawn by [TranscriptDivider], which
+ * which a clear also uses, so the two marks cannot drift apart.
- * a clear also uses, so the two marks cannot drift apart.
  *
- * Blue is [commandColor]: the session acting on itself rather than working on what was asked of it,
+ * Blue is [commandColor]: the session acting on itself rather than working on what was asked of it.
- * which is the same thing the status line says while the compaction runs.
  */
 @Composable
 fun CompactedRow(item: TranscriptItem.CompactedNote, modifier: Modifier = Modifier) {
@@ -23,9 +21,8 @@ fun CompactedRow(item: TranscriptItem.CompactedNote, modifier: Modifier = Modifi
  * What to say about a compaction: the two sizes, and nothing else.
  *
  * The counts are the whole point -- "a million tokens became ten thousand" is the reader's answer
- * to why the wait was worth it -- and they are all this says, because a divider is read in passing.
+ * to why the wait was worth it. When they were not reported this says only that a compaction
- * When they were not reported this says only that a compaction happened, rather than filling in a
+ * happened, rather than filling in a plausible number.
- * plausible number or explaining at length what was missing.
  */
 fun compactionSummary(item: TranscriptItem.CompactedNote): String {
     val pre = item.preTokens
@@ -41,8 +38,8 @@ fun compactionSummary(item: TranscriptItem.CompactedNote): String {
  * A token count as a reader reads one.
  *
  * Shared with the status row rather than formatted at each: the divider and the row report the same
- * quantity about the same moment, and one of them grouping its thousands while the other did not
+ * quantity about the same moment, and one grouping its thousands while the other did not read as
- * read as two different measurements.
+ * two different measurements.
  */
 fun tokens(count: Long): String = "%,d".format(count)
 
@@ -50,15 +47,12 @@ fun tokens(count: Long): String = "%,d".format(count)
  * What the working indicator says while a compaction is running.
  *
  * Elapsed time and nothing else, because elapsed time is all there is: the CLI announces that a
- * compaction has begun and then says nothing until it has finished, so any bar, percentage or
+ * compaction has begun and then says nothing until it has finished, so any bar or estimate here
- * estimate here would be this screen's guess wearing a measurement's clothes. Knowing it has been
+ * would be this screen's guess wearing a measurement's clothes.
- * going forty seconds is what a reader actually wants -- it is the difference between waiting and
- * going to look at why.
  *
  * [seconds] is null when this device did not see the compaction start, which is what opening a
- * session that is already compacting looks like. That case says only "compacting": no number is the
+ * session that is already compacting looks like. That case says only "compacting": a number counted
- * honest answer, and a number counted from the moment the screen opened would be wrong in the
+ * from the moment the screen opened would be wrong in the direction that matters.
- * direction that matters, since a compaction somebody is asking about is a long one.
  */
 fun compactingLabel(seconds: Long?): String =
     when {

app/androidApp/src/main/kotlin/com/example/aiapp/CrashLog.kt

@@ -12,10 +12,9 @@ import java.util.Locale
  * The last crash, kept so the debug button can hand it over.
  *
  * The alternative is asking somebody to reproduce a crash with the phone plugged into a computer
- * and `logcat` running, which is the one thing nobody has set up at the moment it happens -- and a
+ * and `logcat` running, which is the one thing nobody has set up at the moment it happens. This
- * crash report that arrives a day later, without the stack, is a guess. This costs one file write
+ * costs one file write on a process that is already dying, and it turns "it crashes when I open
- * on a process that is already dying, and it turns "it crashes when I open that chat" into the
+ * that chat" into the frame it crashed in.
- * frame it crashed in.
  *
  * Kept until it is read rather than cleared on the next launch: the app restarts before anybody can
  * ask about it, so a log that lives for one session is a log that is never read.
@@ -26,8 +25,7 @@ private const val CRASH_FILE = "last-crash.txt"
  * How much of a stack is kept.
  *
  * This is pasted into a conversation, so it has a budget like any other output written for a
- * reader. The top of a stack is what identifies a crash and the bottom is framework plumbing, so
+ * reader. The top of a stack is what identifies a crash and the bottom is framework plumbing.
- * what gets cut is the part nobody reads.
  */
 private const val CRASH_LIMIT = 4000
 
@@ -35,8 +33,7 @@ private const val CRASH_LIMIT = 4000
  * Records uncaught exceptions, then lets the platform do what it was going to do.
  *
  * Chained rather than replacing: the default handler is what shows the "app has stopped" dialog and
- * ends the process, and an app that swallows that instead sits there in an unknown state. This only
+ * ends the process, and an app that swallows that instead sits there in an unknown state.
- * adds a witness.
  */
 fun installCrashLog(context: Context) {
     val app = context.applicationContext

app/androidApp/src/main/kotlin/com/example/aiapp/DebugStats.kt

@@ -12,10 +12,9 @@ import java.util.concurrent.atomic.AtomicLong
  *
  * Here because the emulator cannot answer the question this is for. Its own scroll sits at the same
  * frame times as the stock Settings app -- 21ms at the median for both -- so every app-level cost
- * is under the floor of what it can measure, and a frame number taken in it says nothing about a
+ * is under the floor of what it can measure. Counts do not have that problem: how many times a row
- * 120Hz phone. Counts do not have that problem: how many times a row was composed, or a reply
+ * was composed, or a reply parsed, is the same number on any machine, and it is the number that
- * parsed, is the same number on any machine, and it is the number that says whether the work is
+ * says whether the work is proportional to what is on screen or to everything ever loaded.
- * proportional to what is on screen or to everything ever loaded.
  *
  * Always on rather than behind a build flag. What is measured is an atomic increment on paths that
  * already allocate lists and parse markdown, and a counter that is only compiled into the build
@@ -90,14 +89,12 @@ object DebugStats {
  *
  * The draw phase is where Compose's measurement lands as well as its recording -- the platform
  * calls `measureAndLayout()` from `dispatchDraw` -- so "draw is high" has never said which of three
- * different things is high. The transcript times its own measure, its own placement and its own
+ * different things is high. The transcript times its own measure, placement and recording, and this
- * recording, and this is the subtraction that was otherwise done by hand in a conversation every
+ * is the subtraction. What is left over is the framework's per-frame bookkeeping after a layout,
- * time a report arrived. What is left over is the framework's per-frame bookkeeping after a layout,
+ * which grows with how many nodes are alive rather than how many are on screen.
- * which grows with how many nodes are alive rather than with how many are on screen.
  *
  * Per frame rather than in total, because the budget it has to fit in is per frame. The recordings
- * are not themselves per-frame -- a measurement happens on the frames that need one -- so these are
+ * are not themselves per-frame, so these are shares of an average frame.
- * shares of an average frame, not a claim about any particular one.
  */
 fun drawAccounting(drawNanos: Long, frames: Int): List<String> {
     if (frames == 0 || drawNanos == 0L) return emptyList()
@@ -122,8 +119,7 @@ fun drawAccounting(drawNanos: Long, frames: Int): List<String> {
  * frames went, and what the app did to produce them.
  *
  * Written for somebody to paste into a conversation, so it is plain text with the units on every
- * number -- a report whose reader has to ask what the columns mean costs another round trip, and
+ * number -- a report whose reader has to ask what the columns mean costs another round trip.
- * the whole point of it is to save one.
  */
 fun debugReport(
     device: String,

app/androidApp/src/main/kotlin/com/example/aiapp/Dividers.kt

@@ -21,11 +21,7 @@ import androidx.compose.ui.unit.dp
  * reader scrolling back, both mean "the session no longer has what is above this", and which of the
  * two it was is said by the words and the colour.
  *
- * The rules take [color] too, so the whole divider reads as one mark of one kind rather than a
+ * The rules take [color] too, so the whole divider reads as one mark of one kind.
- * coloured phrase sitting in an unrelated grey line.
- *
- * Written once here rather than styled at each of them, so the two cannot drift into looking like
- * different kinds of thing.
  */
 @Composable
 fun TranscriptDivider(text: String, color: Color, modifier: Modifier = Modifier) {
@@ -44,9 +40,8 @@ fun TranscriptDivider(text: String, color: Color, modifier: Modifier = Modifier)
  * The mark a clear leaves.
  *
  * Red, and no counts: a clear takes the conversation out of what the session is given, and unlike a
- * compaction it summarises nothing and measures nothing, so there is nothing to report but the
+ * compaction it summarises nothing and measures nothing. Everything above stays on screen and stays
- * fact. Everything above stays on screen and stays scrollable -- the reader can see that, which is
+ * scrollable -- the reader can see that, which is why this does not say it.
- * why this does not say it.
  */
 @Composable
 fun ClearedRow(modifier: Modifier = Modifier) {

app/androidApp/src/main/kotlin/com/example/aiapp/Drafts.kt

@@ -10,12 +10,11 @@ private const val DRAFTS = "session-drafts"
  *
  * On this device rather than on the backend, which is where this app otherwise keeps state so that
  * every device sees it. A draft is the case that rule is not about: it is the contents of a text
- * box on the phone somebody is holding, written on every keystroke, and half a sentence surfacing
+ * box on the phone somebody is holding, and half a sentence surfacing on another device would be a
- * on another device would be a surprise rather than a convenience. What has been *sent* is the
+ * surprise. What has been *sent* is the server's.
- * server's, and that is the part which has to outlive this phone.
  *
- * Kept per session id, because the thing being typed belongs to the conversation it is aimed at:
+ * Kept per session id: one shared box would hand a message meant for one session to whichever was
- * one shared box would hand a message meant for one session to whichever was opened next.
+ * opened next.
  */
 fun loadDraft(context: Context, sessionId: String): String =
     context.getSharedPreferences(DRAFTS, Context.MODE_PRIVATE).getString(sessionId, "").orEmpty()
@@ -23,11 +22,9 @@ fun loadDraft(context: Context, sessionId: String): String =
 /**
  * Records [text] as the draft for [sessionId], or forgets it when there is nothing left to keep.
  *
- * The path out is emptying the box, which is what sending does -- so a sent message removes its own
+ * The path out is emptying the box, which is what sending does. A session *deleted* while it held a
- * entry and nothing accumulates for a session in ordinary use. A session *deleted* while it held a
+ * draft does leave its key behind: pruning those means a pass over the live session list, and the
- * draft does leave its key behind: pruning those means a pass over the live session list, which
+ * residue is a few bytes per session ever abandoned mid-sentence.
- * this file would otherwise have no reason to know about, and the residue is a few bytes per
- * session ever abandoned mid-sentence. That is a trade rather than an oversight.
  */
 fun saveDraft(context: Context, sessionId: String, text: String) {
     context.getSharedPreferences(DRAFTS, Context.MODE_PRIVATE).edit {

app/androidApp/src/main/kotlin/com/example/aiapp/Durations.kt

@@ -5,13 +5,12 @@ package com.example.aiapp
  *
  * A tool's timeout arrives as `480000`, which nobody reads as eight minutes. The rule has two
  * halves, because a short span and a long one are read for different things. Under a minute the
- * question is "roughly how long", so only the largest unit is shown and a fraction of it carries
+ * question is "roughly how long", so only the largest unit is shown and a fraction carries the rest
- * the rest -- `2.5s`, `30ms`. At a minute or more the question is "how long exactly", so every unit
+ * -- `2.5s`. At a minute or more the question is "how long exactly", so every unit with something
- * that has something in it is written out -- `5d 12h 4m`. Units that are empty are left out rather
+ * in it is written out -- `5d 12h 4m`. Empty units are left out rather than written as zero.
- * than written as zero, since the labels say which is which and `5d 0h 4m` is only longer.
  *
  * Sub-second precision is dropped past a minute: nothing that takes days is measured in
- * milliseconds, and carrying them would make the common case the widest one.
+ * milliseconds.
  */
 fun formatMillis(ms: Long): String {
     if (ms < 0) return "-" + formatMillis(-ms)

app/androidApp/src/main/kotlin/com/example/aiapp/EventStream.kt

@@ -12,7 +12,7 @@ private const val RESET_EVENT = "reset"
  *
  * The connection and its framing belong to [Sse]; what stays here is what this stream's frames
  * mean. [close] from any thread ends it, and the caller owns reconnecting -- with the last seq it
- * saw as the new cursor. See SessionScreen.
+ * saw as the new cursor.
  */
 class EventStream(settings: ServerSettings, private val sessionId: String) {
     private val stream = Sse(settings)
@@ -24,20 +24,19 @@ class EventStream(settings: ServerSettings, private val sessionId: String) {
      *
      * [onReset] fires when the server answers that the cursor is too far behind to continue from:
      * everything already displayed is stale and the events that follow are a fresh window, so the
-     * caller drops what it holds and rebuilds -- the same thing it does when the screen opens. It
+     * caller drops what it holds and rebuilds. It arrives before those events, so a caller that
-     * arrives before those events, so a caller that clears on it stays in order.
+     * clears on it stays in order.
      */
     fun run(
         after: Long,
         onOpen: () -> Unit,
         onReset: () -> Unit,
-        // The frame's own text as well as the event parsed from it: the transcript cache stores
+        // The frame's own text as well as the event parsed from it: the transcript cache stores the
-        // the one and the screen folds the other, and they have to be the same line.
+        // one and the screen folds the other, and they have to be the same line.
         onEvent: (raw: String, event: SeqEvent) -> Unit,
     ) {
         stream.run("/sessions/$sessionId/events?after=$after", onOpen) { name, data ->
-            // A named frame carries no payload and a data frame has no name, so this is one or
+            // A named frame carries no payload and a data frame has no name.
-            // the other.
             if (name == RESET_EVENT) onReset()
             else if (data.isNotEmpty()) onEvent(data, parseSeqEvent(data))
         }

app/androidApp/src/main/kotlin/com/example/aiapp/Events.kt

@@ -2,10 +2,9 @@ package com.example.aiapp
 
 import org.json.JSONObject
 
-// The common event model, mirrored from server/src/session/driver.rs --
+// The common event model, mirrored from server/src/session/driver.rs -- the app renders purely from
-// the app renders purely from this stream (replayed from the transcript by
+// this stream (replayed from the transcript by cursor, then live), so there is no separate "load
-// cursor, then live), so there is no separate "load history" shape to keep
+// history" shape to keep in sync with it.
-// in sync with it.
 
 /** One transcript line: the event plus its resume cursor and time. */
 data class SeqEvent(val seq: Long, val ts: Double, val event: SessionEvent)
@@ -13,8 +12,7 @@ data class SeqEvent(val seq: Long, val ts: Double, val event: SessionEvent)
 /**
  * One choice offered in answer to a question.
  *
- * More than a label because the reader is deciding rather than confirming: what an option means,
+ * More than a label because the reader is deciding rather than confirming. Both are absent on a
- * and what picking it would produce, are the things that decide it. Both are absent on a
  * permission, whose Allow and Deny mean exactly what they say.
  */
 data class QuestionOption(val label: String, val description: String?, val preview: String?)
@@ -30,13 +28,12 @@ sealed class SessionEvent {
          */
         val id: String?,
         /**
-         * What was attached to it, by the ref the files route serves: images, and since 2026-09-03
+         * What was attached to it, by the ref the files route serves: images, and any file, told
-         * any file, told apart by [isImageRef].
+         * apart by [isImageRef].
          *
          * On the message rather than beside it: these arrived as separate image events until
          * 2026-08-30, which drew somebody's screenshot as a row floating above the bubble that sent
-         * it, and left this app deciding from adjacency alone which message an image went with --
+         * it, and left this app deciding from adjacency which message an image went with.
-         * something the sender knew and could simply have said.
          */
         val attachments: List<String>,
     ) : SessionEvent()
@@ -45,11 +42,10 @@ sealed class SessionEvent {
      * A message the server has accepted and the session has not read yet.
      *
      * From the server, not from this app's memory of what it sent. The pending bubble used to be
-     * screen state, so leaving the session or restarting the app drew nothing waiting while the
+     * screen state, so leaving the session drew nothing waiting while the message was still queued
-     * message was still queued -- and nothing waiting is what "there is nothing" looks like.
+     * -- and nothing waiting is what "there is nothing" looks like.
      *
-     * Resolved by the [UserMessage] carrying the same id, exactly as [CommandQueued] is resolved by
+     * Resolved by the [UserMessage] carrying the same id.
-     * [CommandSent].
      */
     data class MessageQueued(val id: String, val text: String, val attachments: List<String>) :
         SessionEvent()
@@ -59,8 +55,7 @@ sealed class SessionEvent {
      *
      * Recorded by the server for the same reason [MessageQueued] is: a phone that reconnects
      * replays both, and without this one it would put back a bubble for a message that is never
-     * coming -- with nothing left to resolve it, since the [UserMessage] that normally does is
+     * coming.
-     * exactly what was cancelled.
      */
     data class MessageDropped(val id: String) : SessionEvent()
 
@@ -108,17 +103,14 @@ sealed class SessionEvent {
          *
          * The live Claude Code path only learns a turn was somebody else's when the turn ends, so
          * the event arrives below everything it caused; this is what puts it back above it. Null
-         * for a message read out of a session file, which is already in the right place, and for
+         * for a message read out of a session file, and for one that started no turn.
-         * one that started no turn. See the server's `Event::PeerMessage`.
          */
         val turnStart: Long? = null,
     ) : SessionEvent()
 
     /**
-     * A command the session was asked to run on itself and cannot run yet.
+     * A command the session was asked to run on itself and cannot run yet. Resolved by
-     *
+     * [CommandSent] with the same id; a command that ran straight away has only that one.
-     * Resolved by [CommandSent] with the same id. A command that ran straight away has only that
-     * one, so nothing here ever draws a bubble that resolves in the same frame.
      */
     data class CommandQueued(val id: String, val text: String) : SessionEvent()
 
@@ -130,29 +122,26 @@ sealed class SessionEvent {
     /**
      * What the session is set to, as the session itself reports it.
      *
-     * Either field alone: the two are confirmed separately and by different things. Asking for a
+     * Either field alone: the two are confirmed separately. Asking for a change is not having one,
-     * change is not having one, so this -- not the request -- is what the pickers show.
+     * so this -- not the request -- is what the pickers show.
      */
     data class Settings(val model: String?, val permissionMode: String?) : SessionEvent()
 
     /**
      * What a turn cost, and how much the model was holding when it ended.
      *
-     * [context] is prompt plus both cache figures, measured by the backend from the turn's own
+     * [context] is prompt plus both cache figures. Carried on the event rather than summed by the
-     * usage. Carried on the event rather than summed by the reader, because it is not a sum: a
+     * reader, because it is not a sum: a conversation's context drops at a compaction and a clear,
-     * conversation's context drops at a compaction and a clear, so adding turns up would report a
+     * so adding turns up would report a figure the session stopped being true of. Null where the
-     * figure the session stopped being true of. Null where the dialect did not say, and on entries
+     * dialect did not say, which leaves the context unmeasured rather than unchanged.
-     * recorded before the backend sent it -- which leaves the context unmeasured rather than
-     * unchanged.
      */
     data class UsageDelta(val tokens: Long, val context: Long?) : SessionEvent()
 
     /**
      * A compaction that finished, and how much context it recovered.
      *
-     * The counts are nullable because the server sends them only when it was told them: a
+     * The counts are nullable because the server sends them only when it was told them: a zero here
-     * compaction whose size nobody measured has to be able to say so, since a zero here would read
+     * would read as "recovered nothing" and a made-up number would read as a measurement.
-     * as "recovered nothing" and a made-up number would read as a measurement.
      */
     data class Compacted(
         val preTokens: Long?,
@@ -163,9 +152,7 @@ sealed class SessionEvent {
 
     /**
      * The conversation was cleared. Everything above this is still here to read and is no longer in
-     * the session's context.
+     * the session's context. An object rather than a class because what it means is entirely its
-     *
-     * An object rather than a class because it carries nothing: what it means is entirely its
      * position in the transcript.
      */
     data object Cleared : SessionEvent()
@@ -173,17 +160,15 @@ sealed class SessionEvent {
     data class Error(val message: String) : SessionEvent()
 
     /**
-     * An event type this app build doesn't know -- a newer server. Kept (not thrown) so one new
+     * An event type this app build doesn't know -- a newer server. Kept rather than thrown so one
-     * event kind degrades to a placeholder row instead of killing the stream.
+     * new event kind degrades to a placeholder row instead of killing the stream.
      */
     data class Unknown(val type: String) : SessionEvent()
 }
 
 /**
- * A JSON array of strings under [name], empty when the field is absent.
+ * A JSON array of strings under [name], empty when the field is absent -- the ordinary case, since
- *
+ * the server omits the field rather than sending an empty list.
- * Absent is the ordinary case -- most messages carry no attachment, and the server omits the field
- * rather than sending an empty list -- so this is the shape every caller wants.
  */
 private fun JSONObject.stringList(name: String): List<String> {
     val array = optJSONArray(name) ?: return emptyList()
@@ -212,8 +197,8 @@ fun parseSeqEvent(json: String): SeqEvent {
                 SessionEvent.ToolStart(
                     id = body.getString("id"),
                     tool = body.getString("tool"),
-                    // Kept as raw JSON text: the input shape is the tool's own
+                    // Kept as raw JSON text: the input shape is the tool's own business, and the UI
-                    // business, and the UI only ever shows it verbatim.
+                    // only ever shows it verbatim.
                     input = body.get("input").toString(),
                 )
             "toolUpdate" -> SessionEvent.ToolUpdate(body.getString("id"), body.getString("output"))
@@ -282,36 +267,33 @@ fun parseSeqEvent(json: String): SeqEvent {
     return SeqEvent(seq = body.getLong("seq"), ts = body.getDouble("ts"), event = event)
 }
 
+/**
+ * Whether [state] is one the session is doing work in -- the states a turn is still open under.
+ *
+ * One predicate because two readers have to agree on the list: the session screen's working
+ * indicator, and the fold's decision that the newest reply is finished. Two copies would drift the
+ * first time the server grows a state, and the drift would be a reply that never splits or one
+ * split mid-stream.
+ */
+fun sessionWorking(state: String): Boolean = state == "running" || state == "compacting"
+
 /**
  * The context after [event], given what it was before.
  *
  * The same rule the server folds with, because the screen has to keep up between page loads: the
- * summary it opened with is a measurement from before this stream started, and every event that
+ * summary it opened with is a measurement from before this stream started.
- * moves the figure arrives here.
  *
  * The two that lower it are the point. A clear takes the conversation away and a compaction
  * replaces it with a summary, so a figure measured before either stopped being true at that moment
  * -- and carrying it forward is how a session that had just been cleared went on reporting the
  * context it no longer had.
  *
- * Null is "we don't know", which is a state each of them can reach: nothing measured yet, a
+ * Null is "we don't know", which each of them can reach.
- * compaction that finished without saying how much it recovered, or a clear nobody has run a turn
- * since.
  */
-/**
- * Whether [state] is one the session is doing work in -- the states a turn is still open under.
- *
- * One predicate because two readers have to agree on the list: the session screen's working
- * indicator, and the fold's decision that the newest reply is finished
- * ([TranscriptItem.AssistantMsg.settled]). Two copies would drift the first time the server grows a
- * state, and the drift would be a reply that never splits or one split mid-stream.
- */
-fun sessionWorking(state: String): Boolean = state == "running" || state == "compacting"
-
 fun contextAfter(current: Long?, event: SessionEvent): Long? =
     when (event) {
-        // Falls back to what we had, so a turn the dialect reported no usage for is stale by a
+        // Falls back to what we had, so a turn the dialect reported no usage for is stale by a turn
-        // turn -- which every context figure is -- rather than unknown.
+        // -- which every context figure is -- rather than unknown.
         is SessionEvent.UsageDelta -> event.context ?: current
         is SessionEvent.Compacted -> event.postTokens
         is SessionEvent.Cleared -> null

app/androidApp/src/main/kotlin/com/example/aiapp/FileEditor.kt

@@ -26,7 +26,7 @@ import androidx.compose.ui.text.style.TextAlign
 /**
  * The largest file this app will open in the editor, in bytes.
  *
- * Measured on the emulator on 2026-09-04, in a debug build, on generated Rust:
+ * Measured on the emulator 2026-09-04, in a debug build, on generated Rust:
  *
  * | file   | lines  | scan per keystroke | worst frame record | typing            |
  * |--------|--------|--------------------|--------------------|-------------------|
@@ -35,15 +35,13 @@ import androidx.compose.ui.text.style.TextAlign
  * | 1 MB   | 28,660 | --                 | --                 | stops responding  |
  *
  * The number that decides this is the **frame record**, not the scan: highlighting a 128 kB file
- * costs 40ms a keystroke, which is noticeable and survivable, while laying the same text out in one
+ * costs 40ms a keystroke, which is survivable, while laying the same text out in one
- * `BasicTextField` costs two seconds. So switching highlighting off above a size -- which is what
+ * `BasicTextField` costs two seconds. So switching highlighting off above a size -- what
- * EXPLORER.md expected to have to decide -- would not have saved it; the cost is Compose laying out
+ * EXPLORER.md expected to have to decide -- would not have saved it; every arrangement of a single
- * one enormous text, and every arrangement of a single text field pays it. A line-by-line editor is
+ * text field pays that cost. A line-by-line editor is the way past this.
- * the way past this and is a good deal more than this feature needed.
  *
- * 32 kB rather than something between it and 128 kB, because 32 kB is the largest size that was
+ * 32 kB because it is the largest size actually measured as usable. The viewer's own limit stays
- * actually measured as usable. The viewer's own limit stays the server's `FILE_LIMIT` of 1 MiB:
+ * the server's `FILE_LIMIT` of 1 MiB: reading a big file is fine, and only editing one is not.
- * reading a big file is fine, and it is only editing one that is not.
  */
 const val EDIT_LIMIT = 32L * 1024
 
@@ -53,18 +51,15 @@ const val EDIT_LIMIT = 32L * 1024
  * `BasicTextField(TextFieldValue)` with a [VisualTransformation] is the one Compose arrangement
  * that colours a field's own text rather than replacing the field with something that only looks
  * like one: the transformation returns the text unchanged and the scanner's spans as styles, so
- * [OffsetMapping.Identity] is correct by construction -- no character moves, so no offset does. The
+ * [OffsetMapping.Identity] is correct by construction. The newer `TextFieldState` API has no hook
- * newer `TextFieldState` API has no hook for styles at all, which is why this is the older one.
+ * for styles at all.
  *
- * The cost is that the whole file is re-scanned on every keystroke. For a file under the server's
+ * The cost is that the whole file is re-scanned on every keystroke, which is what [EDIT_LIMIT] is
- * limit that is expected to be a few milliseconds; see EXPLORER.md's "Numbers to measure", which is
+ * sized against.
- * where a size below which highlighting is switched off would be decided if it turns out to be
- * needed.
  *
  * The gutter is one `Text` of `1\n2\n…` beside the field rather than a number per row, because
- * there are no rows here -- the field is one text object. It stays put while the text scrolls
+ * there are no rows here -- the field is one text object. It lines up for the same reason the
- * sideways, and it lines up for the same reason the viewer's does: nothing wraps, so a logical line
+ * viewer's does: nothing wraps, so a logical line is a visual line.
- * is a visual line.
  */
 @Composable
 fun FileEditor(

app/androidApp/src/main/kotlin/com/example/aiapp/FileLines.kt

@@ -12,10 +12,8 @@ import androidx.compose.ui.text.buildAnnotatedString
  * and again on every recomposition.
  *
  * Why per line at all: the viewer is a `LazyColumn` of lines rather than one `Text`, because text
- * layout is linear in the text and a twenty-thousand-line file in one `Text` measures all of it to
+ * layout is linear in the text. That means each row needs *its* colours, and the scanner answers in
- * draw a screenful. That means each row needs *its* colours, and the scanner answers in offsets
+ * offsets into the whole file -- so the spans are bucketed here, once, in one pass.
- * into the whole file -- so the spans are bucketed here, once, in one pass over an already-ordered
- * list, rather than each row searching the whole list for the part that is its.
  */
 class FileLines
 private constructor(
@@ -37,11 +35,9 @@ private constructor(
         get() = lines.size
 
     /**
-     * One line, coloured.
+     * One line, coloured. Built when the row is composed rather than up front: a file has far more
-     *
+     * lines than a screen shows, and an `AnnotatedString` per line for all of them is the cost the
-     * Built when the row is composed rather than up front: a file has far more lines than a screen
+     * lazy list exists to avoid.
-     * shows, and an `AnnotatedString` per line for all of them is the cost the lazy list exists to
-     * avoid.
      */
     fun line(index: Int): AnnotatedString {
         val text = lines[index]
@@ -60,16 +56,13 @@ private constructor(
          *
          * Exactly one trailing newline is dropped before splitting, so a file that ends the way
          * text files are supposed to end has the number of lines its author would count -- `wc -l`
-         * agrees, and so does every editor. Without that, every well-formed file gained a phantom
+         * agrees. Without that, every well-formed file gained a phantom empty last line. An empty
-         * empty last line, which is a wrong line number on every file in the repository. An empty
+         * file is one empty line numbered 1, which is what it is.
-         * file is one empty line numbered 1, which is what it is: a file with nothing in it still
-         * has somewhere for a cursor to go.
          */
         fun of(text: String, language: Language?): FileLines =
-            // Timed, and always, for the same reason everything else here is: the cost of opening
+            // Timed, and always, for the reason everything else here is: the cost of opening a
-            // a large file is the number that decides whether the server's size limit is right,
+            // large file is the number that decides whether the server's size limit is right, and
-            // and an instrument that is only in the build nobody is running answers nothing. It
+            // an instrument that is only in the build nobody is running answers nothing.
-            // lands in the render report beside the transcript's own figures.
             DebugStats.timed("file scanned and cut into lines") {
                 val body = text.removeSuffix("\n")
                 val lines = body.split('\n')
@@ -80,10 +73,9 @@ private constructor(
         /**
          * How many columns a line occupies.
          *
-         * A tab counts as eight rather than as one, and deliberately upwards: this decides how far
+         * A tab counts as eight rather than one, and deliberately upwards: this decides how far the
-         * the viewer can scroll, and over-estimating leaves a little empty space past the longest
+         * viewer can scroll, and over-estimating leaves a little empty space past the longest line
-         * line where under-estimating makes the end of that line unreachable. Compose draws a tab
+         * where under-estimating makes the end of that line unreachable.
-         * as a single advance, so eight is the generous reading rather than the accurate one.
          */
         private fun columnsOf(line: String): Int {
             var count = 0
@@ -95,10 +87,9 @@ private constructor(
          * The scanner's spans, in file offsets, as spans per line in line offsets.
          *
          * One walk down both lists, which is what the scanner's guarantee buys: its spans come out
-         * ordered, non-overlapping and inside the text, so a span can only belong to the line the
+         * ordered, non-overlapping and inside the text. A span crossing a line break is cut at each
-         * walk has reached or to ones after it. A span crossing a line break -- a block comment, a
+         * break and appears in each line it covers, because a row is drawn on its own and cannot
-         * multi-line string -- is cut at each break and appears in each line it covers, because a
+         * inherit a colour from the row above.
-         * row is drawn on its own and cannot inherit a colour from the row above.
          */
         private fun bucket(lines: List<String>, spans: List<Span>): List<List<Span>> {
             val out = ArrayList<List<Span>>(lines.size)

app/androidApp/src/main/kotlin/com/example/aiapp/FileViewer.kt

@@ -50,15 +50,12 @@ fun codeStyle(): TextStyle =
 /**
  * [content] scanned off the main thread, then drawn.
  *
- * Measured on the emulator on 2026-09-04: [FileLines.of] takes **460ms** on a 1 MiB Rust file
+ * Measured on the emulator 2026-09-04: [FileLines.of] takes **460ms** on a 1 MiB Rust file (28,660
- * (28,660 lines) and 11ms on 32 kB. Called from a `remember` inside the composition, as it was
+ * lines) and 11ms on 32 kB. Called from a `remember` inside the composition, as it was first
- * first written, that is 460ms of frozen screen at the size the server is willing to send -- long
+ * written, that is 460ms of frozen screen at the size the server is willing to send -- long enough
- * enough that the accessibility tree cannot be read, which is what "the app has stopped" looks like
+ * that the accessibility tree cannot be read, which is what "the app has stopped" looks like.
- * from outside. So it runs on [Dispatchers.Default] and the spinner is what the reader sees
- * meanwhile, in the place the file will appear.
  *
- * Keyed on the text and the language, so re-reading the same file does not rescan it and a file
+ * Keyed on the text and the language, so re-reading the same file does not rescan it.
- * that changed does.
  */
 @Composable
 fun ScannedFile(content: String, language: Language?, modifier: Modifier = Modifier) {
@@ -76,39 +73,31 @@ fun ScannedFile(content: String, language: Language?, modifier: Modifier = Modif
  * A file, one line per row, coloured by the same scanner that colours a reply's code fences.
  *
  * A `LazyColumn` of lines rather than one `Text`, because text layout is linear in the text: a
- * twenty-thousand-line file in a single `Text` measures all of it to draw a screenful, and the
+ * twenty-thousand-line file in a single `Text` measures all of it to draw a screenful. The cost is
- * scroll never recovers. The cost of the choice is that each row needs its own colours, which is
+ * that each row needs its own colours, which is what [FileLines] works out once and off this
- * what [FileLines] works out once and off this thread.
+ * thread.
  *
  * Lines do not wrap. They share one horizontal scroll state, so the whole file moves sideways as a
  * block and a long line does not silently become three -- which would put the gutter's numbers
- * against the wrong text, the one thing a numbered listing must never do. Because nothing wraps, a
+ * against the wrong text.
- * logical line is one visual line and the two cannot drift.
  *
  * **Every row is given the same content width**, and that is what makes the shared scroll state
  * behave. `Modifier.horizontalScroll` is a node per row, and each one coerces the shared offset
  * into *its own* range -- `content width - viewport` -- so with rows of their natural widths a
- * short line's range is zero and it never moves at all while a long one beside it does. Each row
+ * short line's range is zero and it never moves while a long one beside it does. Each row also
- * also writes `maxValue` on the shared state as it measures, so how far the file could be dragged
+ * writes `maxValue` as it measures, so how far the file could be dragged was decided by whichever
- * was decided by whichever row happened to measure last and changed as the list scrolled. Both
+ * row measured last. Both disappear once every row is [FileLines.columns] wide. Reported by Iris on
- * disappear once every row is [FileLines.columns] wide: one range, one maximum, and the file moves
+ * 2026-09-04 as "it seems to affect different rows differently", which is what a per-row range
- * as the block this comment always claimed it was. Reported by Iris on 2026-09-04 as "it seems to
+ * looks like.
- * affect different rows differently", which is exactly what a per-row range looks like.
  *
  * The stretch at the ends of the travel is **one** effect for the whole file, rendered on the box
- * around the list rather than by each row. `horizontalScroll` makes its own per node otherwise, so
+ * around the list rather than by each row -- `horizontalScroll` makes its own per node otherwise,
- * only the line under the finger stretched and the rest of the file sat still beside it -- the same
+ * so only the line under the finger stretched. Only possible because every row now has the same
- * complaint as the offsets above, one layer further out. Handing every row the same effect and
+ * range.
- * rendering it once is what makes the file bend as the block it scrolls as. Only possible because
- * every row now has the same range: rows that disagreed about where the end was would disagree
- * about when to stretch.
  *
  * The gutter is **beside** the scrolling box rather than inside its rows, which is what keeps the
- * numbers out of both effects: they do not travel with the text and they do not bend with it. The
+ * numbers out of both effects. The rows leave a spacer and [LineGutter] draws them there; its width
- * rows leave a spacer where the numbers will go and [LineGutter] draws them there. Its width is
+ * is measured from the digit count of the line count in the style it is drawn in.
- * measured from the digit count of the line count in the very style it is drawn in, so a nine-line
- * file and a twelve-thousand-line file each get exactly what they need and nothing is nudged by
- * hand.
  *
  * Moving them out also takes them out of the [SelectionContainer], so selecting part of a file and
  * copying it gives the code rather than the code with a number in front of every line.
@@ -139,8 +128,8 @@ fun FileViewer(lines: FileLines, modifier: Modifier = Modifier) {
                                 softWrap = false,
                                 // The scroll outside the width: the scrolling node's viewport is
                                 // what the row has room for, and its content is the whole file's
-                                // widest line. The shared effect is given to every row and
+                                // widest line. The shared effect is given to every row and rendered
-                                // rendered by none of them -- see the box above.
+                                // by none of them -- see the box above.
                                 modifier =
                                     Modifier.horizontalScroll(scroll, overscroll).width(content),
                             )
@@ -157,24 +146,20 @@ fun FileViewer(lines: FileLines, modifier: Modifier = Modifier) {
  * The line numbers, drawn beside the file rather than in it.
  *
  * They have to be outside the box the stretch is rendered on, or they bend with the text; and they
- * have to stay exactly level with the lines they number, which is the one thing a numbered listing
+ * have to stay exactly level with the lines they number. Those two pull in opposite directions.
- * may never get wrong. Those two pull in opposite directions -- out of the list, but pinned to it.
  *
  * A [SubcomposeLayout] is what settles it. *Which* numbers exist and *where* each goes both come
  * from the list's own `layoutInfo`, read in the measure block -- and subcomposition happens during
- * measurement, so this is not composing from a value it read a frame ago, it is composing from the
+ * measurement, so this composes from the answer the list has just produced rather than one it read
- * answer the list has just produced. A `Column` translated by the scroll position could not do
+ * a frame ago. A `Column` translated by the scroll position could not: the translation would be
- * that: the translation would be a layout read and current while the set of numbers would be a
+ * current while the set of numbers was a composition behind, so during a fling the numbers would
- * composition behind it, so during a fling the numbers would slide against their lines.
+ * slide against their lines.
  *
- * The list is measured before this is -- they are siblings in a `Box` and it is declared first --
+ * The list is measured before this is -- they are siblings in a `Box` and it is declared first.
- * and a scroll that remeasures the list on its own does so synchronously, ahead of the layout pass,
- * which is the same reason a lazy list does not lag its own content.
  *
- * `onSurfaceVariant`, because a number is not part of the file: it is this app numbering it, and
+ * `onSurfaceVariant`, because a number is not part of the file. The background is painted because
- * the text's own colour would put it in the same voice as the code. The background is painted
+ * the stretch can carry the text sideways under this column, and a digit with a smear of code
- * because the stretch can carry the text sideways under this column, and a digit with a smear of
+ * behind it reads as a rendering fault.
- * code behind it reads as a rendering fault.
  */
 @Composable
 private fun LineGutter(rows: LazyListState, width: Dp, style: TextStyle) {
@@ -205,10 +190,9 @@ private fun LineGutter(rows: LazyListState, width: Dp, style: TextStyle) {
 /**
  * How wide the widest line number is, measured rather than guessed.
  *
- * `9` repeated, because digits in a monospace face are all one width and the count's own digits
+ * `9` repeated, because digits in a monospace face are all one width -- what matters is how many
- * would measure the same -- what matters is how many there are. Measuring in the style the numbers
+ * there are. Measuring in the style the numbers are drawn in is what makes this survive a font
- * are drawn in is what makes this survive a font size, a density or a display scale nobody here
+ * size, a density or a display scale nobody here chose.
- * chose.
  */
 @Composable
 fun gutterWidth(lineCount: Int, style: TextStyle): Dp {
@@ -225,15 +209,15 @@ fun gutterWidth(lineCount: Int, style: TextStyle): Dp {
 /**
  * How wide to make every row: the widest line in the file, in this style.
  *
- * One character measured rather than the line itself, because the face is monospace -- every
+ * One character measured rather than the line itself, because the face is monospace and measuring
- * advance is the same -- and measuring the actual widest line of a twenty-thousand-line file is
+ * the actual widest line of a twenty-thousand-line file is work for an answer arithmetic already
- * work for an answer arithmetic already has. Sixty-four of them, divided, so the answer does not
+ * has. Sixty-four of them, divided, so the answer does not carry a whole character's worth of
- * carry a whole character's worth of rounding.
+ * rounding.
  *
  * Capped, because this becomes a fixed width in a layout and Compose cannot represent an arbitrary
- * one: a minified file is a single line of a hundred thousand characters, and asking to lay that
+ * one: a minified file is a single line of a hundred thousand characters, and laying that out as
- * out as one row is a crash rather than a slow scroll. Past the cap the far end of such a line
+ * one row is a crash rather than a slow scroll. Past the cap the far end of such a line cannot be
- * cannot be reached, which is the tolerable half of that trade.
+ * reached, which is the tolerable half of that trade.
  */
 @Composable
 private fun contentWidth(columns: Int, style: TextStyle): Dp {
@@ -252,9 +236,7 @@ private fun contentWidth(columns: Int, style: TextStyle): Dp {
 private const val MAX_CONTENT_PX = 100_000f
 
 /**
- * The space between the numbers and the code.
+ * The space between the numbers and the code. A gap, not an alignment: the two are already aligned
- *
+ * by the row, and this is only so the digits and the first character are not touching.
- * A gap, not an alignment: the two are already aligned by the row, and this is only so the digits
- * and the first character of the line are not touching.
  */
 val GUTTER_GAP = 8.dp

app/androidApp/src/main/kotlin/com/example/aiapp/FilesScreen.kt

@@ -45,7 +45,7 @@ import kotlinx.coroutines.withContext
  * Which machine's files to show, and where to start.
  *
  * A **setup**, not a session: a filesystem is a property of a machine, and a session only says
- * where it was working. That is what makes a second way in -- from the setups tab, say -- one more
+ * where it was working. That is what makes a second way in -- from the setups tab -- one more
  * caller rather than any new code here.
  */
 data class FilesTarget(val setup: String, val setupName: String, val start: String)
@@ -61,13 +61,13 @@ private sealed class Spot(val path: String) {
  * The files on the machine a session runs on: browse them, read one, change one.
  *
  * Drawn **over** the session rather than instead of it (see [AppRoot]), so its event stream keeps
- * flowing, its draft and scroll position stay where they were, and coming back from a file costs
+ * flowing and coming back from a file costs nothing. Back steps one level inside here -- editor to
- * nothing. Back steps one level inside here -- editor to viewer, viewer to the directory it came
+ * viewer, viewer to the directory it came from, directory to the one above -- and only closes from
- * from, directory to the one above it -- and only closes from where it opened.
+ * where it opened.
  *
- * Every directory that has been visited is kept for as long as this is open, so stepping back is
+ * Every directory that has been visited is kept for as long as this is open; the refresh glyph is
- * instant; the refresh glyph is how a directory gets asked again on purpose, and creating something
+ * how one gets asked again on purpose, and creating something refetches the directory it was
- * refetches the directory it was created in, since that is the one thing that changed.
+ * created in.
  */
 @Composable
 fun FilesScreen(settings: ServerSettings, target: FilesTarget, onClose: () -> Unit) {
@@ -121,17 +121,16 @@ fun FilesScreen(settings: ServerSettings, target: FilesTarget, onClose: () -> Un
     Box(
         Modifier.fillMaxSize()
             .background(MaterialTheme.colorScheme.background)
-            // The session under this deliberately takes no keyboard inset (see SessionScreen's
+            // The session under this deliberately takes no keyboard inset, so the explorer adds its
-            // layout note), so the explorer adds its own -- otherwise the editor types under the
+            // own -- otherwise the editor types under the keyboard.
-            // keyboard.
             .imePadding()
     ) {
         Column(Modifier.fillMaxSize()) {
             when (val spot = here) {
                 is Spot.Dir -> {
                     val state = listings[spot.path] ?: LoadState.Loading
-                    // The resolved path once there is one: a directory opened as `~` is called
+                    // The resolved path once there is one: a directory opened as `~` is called what
-                    // what it turned out to be, not what it was asked for.
+                    // it turned out to be, not what it was asked for.
                     val at = (state as? LoadState.Loaded)?.value?.path ?: spot.path
                     FilesHeader(
                         title = baseName(at),
@@ -304,9 +303,8 @@ private fun ColumnScope.DirectoryBody(state: LoadState<Listing>, onOpen: (Spot)
  *
  * A symlink says so instead of giving a size, because the size a listing reports for one is the
  * length of the path it points at -- a number that looks exactly like a file size and is about
- * something else entirely. `other` covers a fifo, a device, and a link whose target is gone: the
+ * something else. `other` covers a fifo, a device, and a link whose target is gone: the row still
- * row still appears, because a directory that hid what it held would be lying about being empty,
+ * appears, because a directory that hid what it held would be lying about being empty.
- * and the word is there because a colour cannot say "this is a different kind of thing".
  */
 private fun trailingOf(entry: DirEntry): String? =
     when {
@@ -350,8 +348,7 @@ private fun EntryRow(glyph: String, name: String, trailing: String?, onClick: ()
  *
  * Its own composable so that everything about one file -- what came back, what has been typed, and
  * whether a save is out -- is remembered under that file's path and thrown away when the reader
- * moves to another. What is *not* here is edit mode itself: back has to know about it, and back
+ * moves to another. What is *not* here is edit mode itself: back has to know about it.
- * belongs to the screen.
  */
 @Composable
 private fun ColumnScope.DocPane(
@@ -423,8 +420,8 @@ private fun ColumnScope.DocPane(
                 onDirty(false)
                 onEditing(false)
             } catch (e: ApiException) {
-                // The one refusal that is a question rather than a message: somebody else's edit
+                // The one refusal that is a question rather than a message: somebody else's edit is
-                // is on the machine, and which of the two survives is not this app's to decide.
+                // on the machine, and which of the two survives is not this app's to decide.
                 if (e.status == 409) conflict = e.message ?: "It changed on the machine."
                 else saveError = e.message
             } finally {
@@ -467,10 +464,10 @@ private fun ColumnScope.DocPane(
         )
     }
 
-    // Why the pencil is off. A disabled control teaches what the thing can do, but it cannot say
+    // Why the pencil is off. A disabled control teaches what the thing can do but cannot say why it
-    // why it is disabled -- and a reader who cannot edit a file they can plainly read will
+    // is disabled -- and a reader who cannot edit a file they can plainly read will otherwise
-    // otherwise conclude the app is broken. Said once, here, rather than waiting for a tap that a
+    // conclude the app is broken. Said once, here, rather than waiting for a tap a disabled button
-    // disabled button never receives.
+    // never gets.
     if (loaded != null && !editable) {
         Text(
             "Too big to edit here (${humanSize(loaded.size)}; the limit is " +
@@ -687,6 +684,5 @@ internal fun baseName(path: String): String {
     return if (trimmed.isEmpty()) "/" else trimmed.substringAfterLast('/')
 }
 
-/** A resolved directory and a name in it, as one path. */
 internal fun join(directory: String, name: String): String =
     if (directory.endsWith("/")) "$directory$name" else "$directory/$name"

app/androidApp/src/main/kotlin/com/example/aiapp/FrameStats.kt

@@ -19,19 +19,15 @@ import androidx.compose.ui.platform.LocalContext
  * The point of splitting it up is that "the scroll is laggy" has two completely different causes
  * and one appearance. If the layout-and-measure and draw figures are small and the total is large,
  * the time is going into rasterising and compositing, and no amount of doing less work per row will
- * move it. If they are large, the work per row is the problem and it is ours to fix. Guessing
+ * move it. If they are large, the work per row is the problem and it is ours to fix.
- * between those two is how a day gets spent rewriting the half that was already fast.
  *
  * The phases are the platform's own: [FrameMetrics] reports each frame's cost in nanoseconds,
- * broken down into the parts the UI thread is responsible for -- handling input, running
+ * broken into the parts the UI thread is responsible for and the parts after it.
- * animations, measuring and laying out, recording the draw -- and the parts after it.
  *
  * One of these for the app, like [DebugStats], because the two are read as one report and
  * [drawAccounting] divides one by the other. Held per screen it was emptied by leaving a session
  * and the counters were not, so a report copied after visiting two sessions divided every session's
- * work by the newest one's frame count -- and printed the result as a per-frame measurement. It
+ * work by the newest one's frame count -- 36.8 seconds of placement inside a 13.5 second window.
- * said 36.8 seconds of placement inside a 13.5 second window, and left "everything else" clamped at
- * 0.00ms (0%), which reads as a screen whose whole cost is this app's own code.
  */
 object FrameStats {
     private val total = ArrayList<Long>()
@@ -54,7 +50,7 @@ object FrameStats {
         total += metrics.getMetric(FrameMetrics.TOTAL_DURATION)
         // How long the frame waited for the UI thread to be free before it could start. Reported
         // because the phases otherwise do not add up to the total, and the gap is the interesting
-        // part: it is the frame being held up by work that is not the frame's.
+        // part: the frame being held up by work that is not the frame's.
         waited += metrics.getMetric(FrameMetrics.UNKNOWN_DELAY_DURATION)
         input += metrics.getMetric(FrameMetrics.INPUT_HANDLING_DURATION)
         animation += metrics.getMetric(FrameMetrics.ANIMATION_DURATION)
@@ -123,7 +119,7 @@ private const val CAP = 20_000
  * Records into [FrameStats] for as long as this screen is on it.
  *
  * The listener is what comes and goes; what it writes into does not, so a report covers the same
- * stretch of time as the counters beside it. See [FrameStats].
+ * stretch of time as the counters beside it.
  *
  * The listener is handed its own thread because the platform calls it for every frame and the
  * documentation is explicit that doing that on the main thread taxes the very thing being measured.

app/androidApp/src/main/kotlin/com/example/aiapp/Highlighter.kt

@@ -47,12 +47,11 @@ data class SyntaxPalette(
 /**
  * [code] with its keywords, strings and comments coloured, or plain if there is no language for it.
  *
- * Shared by a tool call's input ([ToolInputView]) and a reply's fences ([CodeFence]), so the same
+ * Shared by a tool call's input and a reply's fences, so the same code is the same colours wherever
- * code is the same colours wherever it appears.
+ * it appears.
  *
  * Not a composable, and it takes no colour from the theme, because that is what lets [warm] run it
- * off the drawing thread: the syntax palette is fixed, and a fence with no language is plain text
+ * off the drawing thread.
- * which needs no colour of its own -- the style the caller draws it with carries that.
  *
  * The timing is the number the highlighter is judged by: the library this replaced took **174ms**
  * on the emulator for a two-hundred-line Kotlin fence, which is why [ParsedReplies.highlighted]
@@ -82,8 +81,7 @@ fun highlight(code: String, language: Language?): AnnotatedString {
  * to the end of the code, which is also what it looks like while a fence is still being written.
  *
  * In ordinary code the order of recognition is comment, string, attribute, number, word, and
- * finally a single punctuation or mark character. Punctuation and marks are coloured only in
+ * finally a single punctuation or mark character, which are coloured only in ordinary code.
- * ordinary code, never inside a string or a comment.
  */
 fun scan(code: String, rules: Rules): List<Span> = Scanner(code, rules).run()
 
@@ -156,8 +154,8 @@ private class Scanner(private val code: String, private val rules: Rules) {
         at += comment.open.length
         var depth = 1
         while (at < code.length && depth > 0) {
-            // The closer is tried first so that a language whose two delimiters are the same
+            // The closer is tried first so that a language whose two delimiters are the same string
-            // string -- CoffeeScript's `###` -- closes rather than nesting forever.
+            // -- CoffeeScript's `###` -- closes rather than nesting forever.
             if (starts(comment.close)) {
                 depth--
                 at += comment.close.length

app/androidApp/src/main/kotlin/com/example/aiapp/ImportScreen.kt

@@ -49,11 +49,9 @@ private const val DELETING = "deleting"
 /**
  * What the rows further down a batch say while they wait their turn.
  *
- * Its own word rather than the operation's, because it is its own state and the difference is the
+ * Its own word rather than the operation's, because nothing has been done to this session yet, so a
- * kind that matters: nothing has been done to this session yet, so a batch stopped here leaves it
+ * batch stopped here leaves it exactly as it was. Marked from the moment the batch is handed over
- * exactly as it was. Marked from the moment the batch is handed over all the same -- a queued row
+ * all the same -- a queued row that still looked ordinary was still tappable.
- * that still looked ordinary was still tappable, and tapping it would import it a second time
- * behind the batch already coming for it.
  */
 private const val WAITING = "waiting"
 
@@ -62,25 +60,22 @@ private const val WAITING = "waiting"
  *
  * A batch takes rows out of the list as each one lands, so everything below the one that went
  * slides up -- and a tap already on its way then arrives at whichever row moved into that place. On
- * this screen that means importing a session nobody chose, which is not something a second tap can
+ * this screen that means importing a session nobody chose.
- * undo.
  *
  * Swallowed silently rather than shown, because anything drawn on every row a batch passes would be
- * a flicker running down the list. Half a second: long enough to cover a tap already travelling
+ * a flicker running down the list.
- * when the row moved, short enough that it is not in the way of a deliberate one.
  */
 private const val SETTLE_MS = 500L
 
 /**
  * Continuing a Claude Code session the machine already has.
  *
- * The list is the machine's answer, not this app's: it asks a setup what sessions it holds and
+ * The list is the machine's answer, not this app's. Choosing one sends its **id**, never a path, so
- * shows them. Choosing one sends its **id**, never a path, so an enrolled phone cannot turn this
+ * an enrolled phone cannot turn this screen into a file reader.
- * screen into a file reader.
  *
  * Holding a row selects it and puts the screen in selection mode, where the options that act on a
- * selection appear along the bottom. That exists because these arrive in bulk — a machine
+ * selection appear along the bottom. That exists because these arrive in bulk -- a machine
- * accumulates dozens of abandoned sessions — and one confirmation dialog per row is the reason
+ * accumulates dozens of abandoned sessions -- and one confirmation dialog per row is the reason
  * clearing them out was not worth doing.
  */
 @OptIn(ExperimentalFoundationApi::class)
@@ -91,28 +86,25 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
     var chosen by remember { mutableStateOf<Setup?>(null) }
     var sessions by remember { mutableStateOf<LoadState<List<Importable>>>(LoadState.Loading) }
 
-    // What is happening to each row right now, as the word the row shows: "importing" or
+    // What is happening to each row right now, as the word the row shows. A map keyed by id rather
-    // "deleting". A map keyed by id rather than a flag per row, because the rows are rebuilt from
+    // than a flag per row, because the rows are rebuilt from whatever the server last said and this
-    // whatever the server last said and this belongs to the request rather than to the session --
+    // belongs to the request rather than to the session.
-    // the same arrangement the session list uses for its deletes.
     var running by remember { mutableStateOf<Map<String, String>>(emptyMap()) }
-    // Which rows the reader has picked out. Empty means selection mode is off: there is no
+    // Which rows the reader has picked out. Empty means selection mode is off: a selection mode
-    // separate flag, because a selection mode with nothing selected is a state with no controls
+    // with nothing selected is a state with no controls in it and no way to leave except Back.
-    // in it and no way to leave except Back.
     var selected by remember { mutableStateOf<Set<String>>(emptySet()) }
     // Failures that belong to one row rather than to the screen, shown on that row. A batch is
-    // exactly where a single banner fails: nine deletes succeeded and one did not, and the
+    // exactly where a single banner fails: nine deletes succeeded and one did not, and the banner
-    // banner cannot say which.
+    // cannot say which.
     var rowErrors by remember { mutableStateOf<Map<String, String>>(emptyMap()) }
     // Deleting a transcript cannot be undone, so it is asked rather than done. Held as the rows
     // themselves, not a flag, so the dialog can say what it is about.
     var confirming by remember { mutableStateOf<List<Importable>?>(null) }
-    // Same default as the spawn screen, and for the same reason: a phone
+    // Same default as the spawn screen: a phone is the wrong place to answer "allow Bash?" forty
-    // is the wrong place to answer "allow Bash?" forty times.
+    // times.
     var permissionMode by remember { mutableStateOf("auto") }
-    // When each row last slid upwards, as a plain map rather than state: nothing is drawn from
+    // When each row last slid upwards, as a plain map rather than state: nothing is drawn from it,
-    // it, so a tap reading it needs no recomposition and there is no timer to cancel when a
+    // so a tap reading it needs no recomposition.
-    // second removal lands on top of the first.
     val movedAt = remember { mutableMapOf<String, Long>() }
     fun settling(id: String) = System.currentTimeMillis() - (movedAt[id] ?: 0L) < SETTLE_MS
 
@@ -120,8 +112,7 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
      * Fetches the list and takes the row states from it.
      *
      * Taken from the answer rather than kept across the load: the server is what knows what is
-     * running, and this screen may be opening on work another screen -- or another phone --
+     * running, and this screen may be opening on work another phone started.
-     * started. Anything held locally would be a second version of that, and the stale one.
      */
     suspend fun fetchInto(setup: Setup): LoadState<List<Importable>> =
         try {
@@ -167,13 +158,11 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
      * Hands [targets] to the server in one request, marking every row it covers.
      *
      * The request only *starts* the work -- the server runs it and says how each row went on the
-     * change stream, which is what lets this screen be left while a batch is still going. So there
+     * change stream, which is what lets this screen be left while a batch is still going.
-     * is nothing here to wait for and nothing to sequence: the rows are marked, the batch goes, and
-     * everything after that arrives as an event.
      *
      * Marked [WAITING] rather than with the operation's own word until the server confirms. Between
      * the request leaving and the `started` event coming back, "we have asked" is the truth and "it
-     * is importing" is a guess -- and the row is inert either way, which is the part that matters.
+     * is importing" is a guess.
      *
      * The selection is dropped as the work is handed over, not when it finishes: the screen goes
      * back to how it started, and what says the work is happening is the rows it is happening to.
@@ -186,17 +175,14 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
         val ids = targets.map { it.id }
         scope.launch {
             // One request for the whole batch, not one per row. Sent row by row, a handover was
-            // only as atomic as the network: the fourth of six could fail, or the screen could be
+            // only as atomic as the network, and what came back was some rows running and some
-            // left with two still unsent, and what came back was some rows running and some
+            // untouched -- indistinguishable, on the list, from rows nobody had picked.
-            // untouched -- indistinguishable, on the list, from rows nobody had picked. Now
-            // either the server has the batch or it has none of it, and this is the one place
-            // that can be true.
             try {
                 withContext(Dispatchers.IO) { send(ids) }
             } catch (err: Exception) {
                 // The server never took it, so nothing is running and no event will arrive to say
-                // so. This is the one failure the screen must report itself -- and it is now the
+                // so. This is the one failure the screen must report itself -- and it is the whole
-                // whole batch's failure, which is the point: no row was singled out.
+                // batch's failure, which is the point: no row was singled out.
                 running = running - ids.toSet()
                 rowErrors = rowErrors + ids.associateWith { err.message ?: "Couldn't ask" }
                 return@launch
@@ -205,19 +191,17 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
             // Then ask what actually happened, if anything still looks outstanding.
             //
             // The change stream is a broadcast with no memory, so an operation that started and
-            // finished while it was still connecting is one nothing will ever be said about --
+            // finished while it was still connecting is one nothing will ever be said about -- and
-            // and the row sits marked for ever. That is not hypothetical: with responses held
+            // the row sits marked for ever. That is not hypothetical: with responses held back far
-            // back far enough for the stream to open late, one row of a pair of deletes cleared
+            // enough, one row of a pair of deletes cleared and the other stayed on "waiting".
-            // and the other stayed on "waiting".
             //
-            // The listing is the repair, because it carries the same state the events do. Only
+            // The listing is the repair, because it carries the same state the events do. Only when
-            // when something still looks outstanding, so the ordinary case -- where the events
+            // something still looks outstanding, so the ordinary case does not pay for a second
-            // arrived and the rows are already gone -- does not pay for a second listing, which
+            // listing, which is the most expensive call this screen makes.
-            // is the most expensive call this screen makes.
             if (setup != null && targets.any { running.containsKey(it.id) }) {
-                // Quietly: no Loading, because blanking the list to report on rows that are
+                // Quietly: no Loading, because blanking the list to report on rows that are already
-                // already saying what is happening to them is the flicker this screen avoids
+                // saying what is happening to them is the flicker this screen avoids everywhere
-                // everywhere else.
+                // else.
                 sessions = fetchInto(setup)
             }
         }
@@ -225,13 +209,6 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
 
     val provider = chosen?.providers?.firstOrNull { it.kind == "claude_cli" }
 
-    /**
-     * Imports [targets], and goes to the session it made when [thenOpen].
-     *
-     * One function for the tap and for the bar, differing in that one flag: continuing a session
-     * and then looking at it is what a tap on a row means, and a batch has several results and no
-     * reason to pick one of them to become the screen.
-     */
     /** Continues [targets] in the background, leaving the screen where it is. */
     fun importAll(targets: List<Importable>) {
         val setup = chosen ?: return
@@ -283,13 +260,12 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
         }
     }
 
-    // Live changes to what the server is doing to these sessions, for as long as this screen is
+    // Live changes to what the server is doing to these sessions, for as long as this screen is up.
-    // up. The listing already carried the same state when the screen opened -- this is what keeps
+    // The listing already carried the same state when the screen opened -- this is what keeps it
-    // it current afterwards, including for work another screen or another phone started.
+    // current afterwards, including for work another phone started.
     //
     // Failures here are deliberately quiet. There is nothing for a reader to do about a dropped
-    // event stream, and nothing is lost by one: every state it would have carried is in the next
+    // event stream, and every state it would have carried is in the next listing.
-    // listing, which is what Refresh and re-entering the tab already fetch.
     val liveChanges = remember {
         java.util.concurrent.atomic.AtomicReference<ImportableStream?>(null)
     }
@@ -307,8 +283,7 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
                                     running =
                                         running + (change.session to (change.operation ?: WAITING))
                                 // Gone from the machine either way: a delete removed the
-                                // transcript, an import made it a session, and neither is
+                                // transcript, an import made it a session.
-                                // something this list still has to offer.
                                 "finished" -> {
                                     running = running - change.session
                                     forget(change.session)
@@ -323,17 +298,14 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
                         }
                     }
                 } catch (e: kotlinx.coroutines.CancellationException) {
-                    // The screen leaving, not a failure -- and swallowing it would leave this
+                    // The screen leaving, not a failure -- and swallowing it would leave this loop
-                    // loop reconnecting to a stream nobody is watching.
+                    // reconnecting to a stream nobody is watching.
                     throw e
                 } catch (_: Exception) {
-                    // Retried below; the listing is the truth in the meantime.
+                    // Retried below; the listing is the truth in the meantime. Any failure, not
-                    //
+                    // only an [ApiException]: a stream is an optimisation over the listing here,
-                    // Any failure, not only an [ApiException]. A stream is an optimisation over
+                    // and catching only the expected failure means an unexpected one closes the app
-                    // the listing here, so nothing it can do is worth taking the app down for --
+                    // from a screen that is merely loading a list.
-                    // and catching only the failure that was expected means an unexpected one
-                    // reaches the top of the app and closes it, from a screen that is merely
-                    // loading a list.
                 } finally {
                     stream.close()
                 }
@@ -351,9 +323,8 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
     // Nested inside MainScreen's own handler, so it wins while there is a selection.
     BackHandler(enabled = selected.isNotEmpty()) { selected = emptySet() }
 
-    // Measured rather than assumed: the list reserves exactly what the bar covers, so the last
+    // Measured rather than assumed: the list reserves exactly what the bar covers, so the last row
-    // row can still be scrolled to while it is up, and nothing is nudged by a number that was
+    // can still be scrolled to while it is up.
-    // right for one font size.
     var barHeight by remember { mutableStateOf(0.dp) }
     val density = LocalDensity.current
 
@@ -428,8 +399,8 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
             }
         }
 
-        // Beside nothing in particular, because a selection is not one row: the options that act
+        // Beside nothing in particular, because a selection is not one row: the options that act on
-        // on it belong to the screen, and the bottom is where a thumb already is.
+        // it belong to the screen, and the bottom is where a thumb already is.
         if (selected.isNotEmpty()) {
             val picked =
                 (sessions as? LoadState.Loaded)?.value?.filter { it.id in selected }.orEmpty()
@@ -486,8 +457,7 @@ fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (Sessio
  * What can be done to the rows that are selected.
  *
  * Delete and Import only, for now: they are the two things this screen has ever done to a session,
- * and an option that appears here has to work on every row in a selection rather than on the one
+ * and an option that appears here has to work on every row in a selection.
- * somebody was thinking of.
  */
 @Composable
 private fun SelectionBar(
@@ -567,26 +537,23 @@ private fun ImportableList(
                                     Modifier.fillMaxWidth()
                                         .padding(vertical = 4.dp)
                                         .combinedClickable(
-                                            // Off while something is happening to this row --
+                                            // Off while something is happening to this row -- see
-                                            // see [BusyItem], which draws that but deliberately
+                                            // [BusyItem], which draws that but leaves the gestures
-                                            // leaves the gestures alone so the list still
+                                            // alone so the list still scrolls.
-                                            // scrolls.
                                             enabled = running[session.id] == null,
                                             onClick = {
                                                 if (settling(session.id)) return@combinedClickable
                                                 // In selection mode a tap is a selection, so the
-                                                // reader is never one mis-tap away from starting
+                                                // reader is never one mis-tap away from starting a
-                                                // a CLI they were only picking rows for.
+                                                // CLI they were only picking rows for.
                                                 //
-                                                // Outside it, a tap continues the session --
+                                                // Outside it, a tap continues the session -- except
-                                                // except on a row that cannot be continued,
+                                                // on a row that cannot be continued, where it
-                                                // where it selects instead. That row's only
+                                                // selects instead. That row's only remaining action
-                                                // remaining action is Delete, and a tap that
+                                                // is Delete, and a tap that did nothing at all
-                                                // did nothing at all would be a worse answer
+                                                // would be a worse answer. Two `--resume` processes
-                                                // than one that offers the thing it can do.
+                                                // on one transcript each replay the other's writes,
-                                                // Two `--resume` processes on one transcript
+                                                // which is why this must not simply try.
-                                                // each replay the other's writes, which is why
-                                                // this must not simply try.
                                                 if (selecting || session.inUse == "yes")
                                                     onToggle(session)
                                                 else onOpen(session)
@@ -606,8 +573,7 @@ private fun ImportableList(
                                         Spacer(Modifier.width(8.dp))
                                         // Beside the title, because "which one was I just in" is
                                         // the question this list answers and the order already
-                                        // reflects it -- the reader should be able to see the
+                                        // reflects it.
-                                        // ordering they are being given rather than infer it.
                                         Text(
                                             relativeTime(session.modified),
                                             style = MaterialTheme.typography.bodySmall,
@@ -616,12 +582,11 @@ private fun ImportableList(
                                     }
                                     Spacer(Modifier.height(4.dp))
                                     // The path first, and the only thing here that is cut: it is
-                                    // one long value with no natural break, where the lines below
+                                    // one long value with no natural break. Cut at the head,
-                                    // it are short enough to wrap readably. Cut at the head,
+                                    // because a path is identified by its tail and these all share
-                                    // because a path is identified by its tail and these all
+                                    // a long prefix. By the row's real width rather than a
-                                    // share a long prefix. By the row's real width rather than a
+                                    // character count, which was one guess for every font size and
-                                    // character count, which was one guess for every font size
+                                    // screen.
-                                    // and screen.
                                     session.cwd
                                         .takeIf { it.isNotEmpty() }
                                         ?.let { cwd ->
@@ -648,8 +613,7 @@ private fun ImportableList(
                                             color = warningColor,
                                         )
                                     }
-                                    // Reported where it happened, in the server's own words, the
+                                    // Reported where it happened, in the server's own words.
-                                    // way every other failure in this app is shown.
                                     errors[session.id]?.let { message ->
                                         Spacer(Modifier.height(4.dp))
                                         Text(
@@ -673,14 +637,14 @@ private fun statsOf(session: Importable): String =
             // Said, because a name and a last message are different claims: one describes the
             // session, the other is only what happened last in it.
             if (session.named) "named" else null,
-            // What continuing it costs, which is the question this list is really asked. First
+            // What continuing it costs, which is the question this list is really asked. Absent
-            // of the measurements for that reason, and absent rather than zero when nothing has
+            // rather than zero when nothing has been measured -- a session with no turns yet has no
-            // been measured -- a session with no turns yet has no figure, not a figure of none.
+            // figure, not a figure of none.
             session.contextTokens?.let { "${it / 1000}k context" },
             "${session.lines} lines",
             // Kept beside the context figure because the two disagree usefully: most of a large
-            // transcript is history from before a compaction, which the model is no longer
+            // transcript is history from before a compaction, so a big file can be cheap to
-            // given, so a big file can be cheap to continue and a small one expensive.
+            // continue.
             humanSize(session.bytes),
         )
         .joinToString(" · ")
@@ -689,16 +653,14 @@ private fun statsOf(session: Importable): String =
  * Why this session might not be safe to take, if it isn't.
  *
  * Words rather than only a colour: "open somewhere else" and "we could not check" differ in kind,
- * and no shade distinguishes them. The colour is what makes it findable; the words are what make it
+ * and no shade distinguishes them.
- * actionable.
  */
 private fun warningOf(session: Importable): String? =
     when (session.inUse) {
         // What was measured is that a live process on that machine holds this session open. Which
-        // process is not measured, so it isn't claimed: "a terminal — close it there first" sent
+        // process is not measured, so it isn't claimed: "a terminal -- close it there first" sent
-        // people looking for a window that need not exist. It is just as likely another agent, or
+        // people looking for a window that need not exist. Naming a place the reader then can't
-        // this app on a session it spawned. Naming a place the reader then can't find turns a
+        // find turns a correct refusal into a wrong instruction.
-        // correct refusal into a wrong instruction.
         "yes" -> "something on that machine is running it"
         "unknown" -> "can't tell if it's open"
         else -> null

app/androidApp/src/main/kotlin/com/example/aiapp/Languages.kt

@@ -49,10 +49,9 @@ data class Rules(
     /** Tokens that open a comment running to the end of the line. */
     val lineComments: List<String> = emptyList(),
     /**
-     * Whether [lineComments] count only at the start of a word.
+     * Whether [lineComments] count only at the start of a word. The shells need it: `$#`, `${#x}`
-     *
+     * and `a#b` are not comments, and greying the rest of those lines is one of the mistakes this
-     * The shells need it: `$#`, `${#x}` and `a#b` are not comments, and greying the rest of those
+     * scanner exists to stop.
-     * lines is one of the mistakes this scanner exists to stop.
      */
     val lineCommentsAtWordStart: Boolean = false,
     val blockComment: BlockComment? = null,
@@ -63,8 +62,8 @@ data class Rules(
     val rawStrings: Boolean = false,
     /**
      * Rust: `'` opens a character literal only when a backslash or one character and a `'` follow.
-     * Otherwise it is a lifetime or a label and no string starts -- without this, `'a` opens a
+     * Otherwise it is a lifetime or a label -- without this, `'a` opens a string that runs to the
-     * string that runs to the next apostrophe in the block.
+     * next apostrophe in the block.
      */
     val lifetimes: Boolean = false,
 )
@@ -91,11 +90,10 @@ enum class Attributes {
  * The spans [language] colours in [code] -- the one way to ask, whatever the language turns out to
  * be made of.
  *
- * Nearly every language here is tokens: keywords, strings and comments, which is a row of [RULES]
+ * Nearly every language here is tokens, which is a row of [RULES] and the one shared scanner.
- * and the one shared scanner in [scan]. Markdown has none of those, and what a character means
+ * Markdown has none of those, and what a character means there depends on where on the line it
- * there depends on where on the line it sits, so it brings a scanner of its own ([scanMarkdown]).
+ * sits, so it brings a scanner of its own. That is the whole extension point -- a new language is a
- * That is the whole extension point -- a new language is a row of rules or an entry in [SCANNERS],
+ * row of rules or an entry in [SCANNERS], and no caller learns which one it got.
- * and no caller learns which one it got.
  */
 fun spansOf(code: String, language: Language): List<Span> = SCANNERS.getValue(language)(code)
 
@@ -140,8 +138,8 @@ private val RULES: Map<Language, Rules> by lazy {
                 blockComment = C_STYLE,
                 quotes = listOf(DOUBLE, SINGLE),
             ),
-        // `###` opens and closes a block comment and `#` opens a line one, which is why the
+        // `###` opens and closes a block comment and `#` opens a line one, which is why the scanner
-        // scanner tries the block opener first.
+        // tries the block opener first.
         Language.COFFEESCRIPT to
             Rules(
                 keywords = KEYWORDS_COFFEESCRIPT,
@@ -162,8 +160,8 @@ private val RULES: Map<Language, Rules> by lazy {
                 keywords = KEYWORDS_FISH,
                 lineComments = listOf("#"),
                 lineCommentsAtWordStart = true,
-                // fish's single quotes escape only `\'` and `\\`, which is what "skip the
+                // fish's single quotes escape only `\'` and `\\`, which is what "skip the character
-                // character after a backslash" already does.
+                // after a backslash" already does.
                 quotes = listOf(DOUBLE, SINGLE),
             ),
         Language.GO to
@@ -288,10 +286,9 @@ private val RULES: Map<Language, Rules> by lazy {
  * The keyword sets.
  *
  * Every list below other than RON, TOML, fish and JSON came from dev.snipme:highlights 1.1.0
- * (`SyntaxTokens.kt`, Apache-2.0), the library this scanner replaced, so that no fence which is
+ * (Apache-2.0), the library this scanner replaced, so that no fence which is coloured today turns
- * coloured today turns plain. Entries that are not plain words were dropped -- Kotlin's `as?`,
+ * plain. Entries that are not plain words were dropped -- Kotlin's `as?`, Swift's `#if` family,
- * `!in` and `!is`, Swift's `#if` family, Ruby's `defined?`, CoffeeScript's `=` and `->` -- because
+ * Ruby's `defined?` -- because the word scanner cannot reach them.
- * the word scanner cannot reach them and the library only matched them by luck.
  */
 private fun words(list: String): Set<String> =
     list.split(Regex("\\s+")).filterNot(String::isEmpty).toSet()

app/androidApp/src/main/kotlin/com/example/aiapp/LoadState.kt

@@ -8,7 +8,7 @@ package com.example.aiapp
  * empty list, which is the one wrong answer that looks like a right one.
  *
  * [Loading] and [Error] carry no payload, so they are `LoadState<Nothing>` and this is covariant in
- * [T]: one `LoadState.Loading` serves every screen rather than each needing its own.
+ * [T]: one `LoadState.Loading` serves every screen.
  */
 sealed class LoadState<out T> {
     data object Loading : LoadState<Nothing>()

app/androidApp/src/main/kotlin/com/example/aiapp/MainActivity.kt

@@ -28,14 +28,13 @@ import androidx.compose.ui.layout.layout
 import androidx.core.view.WindowCompat
 
 class MainActivity : ComponentActivity() {
-    // Bumped whenever enrollment lands via an aiapp:// intent so the
+    // Bumped whenever enrollment lands via an aiapp:// intent so the composition below re-reads the
-    // composition below re-reads the stored settings.
+    // stored settings.
     private var settingsVersion by mutableIntStateOf(0)
 
-    // The session a notification tap asked for, or null if nothing has. The
+    // The session a notification tap asked for, or null if nothing has. The serial is what makes a
-    // serial is what makes a second tap on the same session's notification a
+    // second tap on the same session's notification a second request: without it the two compare
-    // second request: without it the two compare equal and the composition
+    // equal and the composition below has nothing to react to.
-    // below has nothing to react to.
     private var openRequest by mutableStateOf<SessionOpenRequest?>(null)
     private var opens = 0
 
@@ -43,8 +42,8 @@ class MainActivity : ComponentActivity() {
     private var shareRequest by mutableStateOf<ShareRequest?>(null)
     private var shares = 0
 
-    // Registered up front since permission launchers must be registered
+    // Registered up front since permission launchers must be registered before the activity reaches
-    // before the activity reaches STARTED.
+    // STARTED.
     private val requestLocalNetworkPermission =
         registerForActivityResult(ActivityResultContracts.RequestPermission()) {}
 
@@ -52,8 +51,8 @@ class MainActivity : ComponentActivity() {
      * The service starts either way, and posts nothing if this is refused.
      *
      * Deliberately not gated on the answer: the permission can be granted later from Android's own
-     * settings, and a service that only ever started at the moment it was granted would then stay
+     * settings, and a service that only ever started at the moment it was granted would stay down
-     * down until the app was launched again -- which is the case notifications exist to avoid.
+     * until the app was launched again.
      */
     private val requestNotificationPermission =
         registerForActivityResult(ActivityResultContracts.RequestPermission()) {}
@@ -64,21 +63,17 @@ class MainActivity : ComponentActivity() {
         // Before anything else that could throw, so the first crash of a launch is caught too.
         installCrashLog(this)
 
-        // Transparent status bar on every version; the Surface below paints
+        // Transparent status bar on every version; the Surface below paints through underneath it
-        // through underneath it and content insets itself. Same reasoning
+        // and content insets itself. Same reasoning as dev-updater's MainActivity.
-        // as dev-updater's MainActivity.
         enableEdgeToEdge()
-        // Dark status-bar icons only over a light background, decided from the scheme rather
+        // Dark status-bar icons only over a light background, decided from the scheme rather than
-        // than fixed. It was hardcoded to `true` -- dark icons -- which was right against the
+        // fixed. It was hardcoded to `true`, which was right against the default light surface and
-        // default light surface and became unreadable the moment the app wore Catppuccin Mocha.
+        // became unreadable the moment the app wore Catppuccin Mocha.
-        // Asking the colour means a future palette change cannot reintroduce that: whatever
-        // `background` becomes, the icons follow it.
         WindowCompat.getInsetsController(window, window.decorView).isAppearanceLightStatusBars =
             AiAppColors.background.luminance() > 0.5f
 
-        // Android 17+ silently drops local-network traffic without this;
+        // Android 17+ silently drops local-network traffic without this; requested up front because
-        // requested up front because a denial is invisible at the socket
+        // a denial is invisible at the socket layer (it just times out).
-        // layer (it just times out).
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.CINNAMON_BUN) {
             requestLocalNetworkPermission.launch(Manifest.permission.ACCESS_LOCAL_NETWORK)
         }
@@ -88,16 +83,14 @@ class MainActivity : ComponentActivity() {
         }
 
         handleIntent(intent)
-        // After enrollment, so a first launch that arrives with a token
+        // After enrollment, so a first launch that arrives with a token starts the service with
-        // starts the service with something to connect to rather than
+        // something to connect to rather than stopping it and waiting for the next launch.
-        // stopping it and waiting for the next launch.
         NotificationService.sync(this)
 
         setContent {
             // Selection colours with the theme rather than at each place text is drawn: the
-            // transcript is one selection container, and a selection that ran from a reply into
+            // transcript is one selection container, and a selection that ran from a reply into the
-            // the code block under it would otherwise change colour halfway. See
+            // code block under it would otherwise change colour halfway.
-            // [AiAppSelectionColors].
             MaterialTheme(colorScheme = AiAppColors) {
                 CompositionLocalProvider(LocalTextSelectionColors provides AiAppSelectionColors) {
                     Surface(modifier = Modifier.fillMaxSize()) {
@@ -107,8 +100,7 @@ class MainActivity : ComponentActivity() {
                                 // the frame's draw phase is where Compose's measurement lands, and
                                 // a report saying "draw is high" cannot otherwise say whether the
                                 // cost is the transcript or the chrome around it. The keyboard is
-                                // the case that made it matter -- every frame of the IME animation
+                                // the case that made it matter.
-                                // relays out and re-records this whole box.
                                 Modifier.layout { measurable, constraints ->
                                         val started = System.nanoTime()
                                         val placeable = measurable.measure(constraints)
@@ -135,19 +127,16 @@ class MainActivity : ComponentActivity() {
                                     }
                                     .fillMaxSize()
                                     .statusBarsPadding()
-                                    // The gesture strip at the bottom of most
+                                    // The gesture strip at the bottom of most phones. Without it
-                                    // phones. Without it the send row sits under
+                                    // the send row sits under the swipe area, where a tap is as
-                                    // the swipe area, where a tap is as likely to
+                                    // likely to navigate away as to press a button.
-                                    // navigate away as to press a button.
                                     //
                                     // No imePadding here, deliberately: applied at the root it
                                     // resizes this whole box on every frame of the keyboard
                                     // animation, which re-measures, re-places and re-records every
-                                    // screen's entire tree per frame -- measured above as most of
+                                    // screen's entire tree per frame. Each screen takes the
-                                    // the frame budget. Each screen takes the keyboard itself
+                                    // keyboard itself, so the per-frame cost is scoped to what
-                                    // (AppRoot wraps the ordinary ones; the session screen moves
+                                    // actually moves.
-                                    // only its composer and transcript), so the per-frame cost is
-                                    // scoped to what actually moves.
                                     .navigationBarsPadding()
                         ) {
                             AppRoot(settingsVersion, openRequest, shareRequest)
@@ -158,9 +147,8 @@ class MainActivity : ComponentActivity() {
         }
     }
 
-    // launchMode="singleTop": an enrollment scan, or a notification tapped
+    // launchMode="singleTop": an enrollment scan, or a notification tapped while the app is open,
-    // while the app is open, lands here rather than in a second activity
+    // lands here rather than in a second activity instance.
-    // instance.
     override fun onNewIntent(intent: Intent) {
         super.onNewIntent(intent)
         handleIntent(intent)
@@ -171,8 +159,7 @@ class MainActivity : ComponentActivity() {
      *
      * Three things arrive this way -- a share from another app, and an `aiapp://` URI that is
      * either an enrollment code or a notification naming a session. The URIs are told apart by host
-     * rather than by two entry points, so a further kind is a branch here rather than another
+     * rather than by two entry points, so a further kind is a branch here.
-     * intent to remember to handle.
      */
     private fun handleIntent(intent: Intent?) {
         intent ?: return
@@ -195,8 +182,8 @@ class MainActivity : ComponentActivity() {
         }
         saveServerSettings(this, settings)
         settingsVersion++
-        // Enrolling is the moment there is a backend to watch, and
+        // Enrolling is the moment there is a backend to watch, and re-enrolling elsewhere is the
-        // re-enrolling elsewhere is the moment the old one stops being it.
+        // moment the old one stops being it.
         NotificationService.sync(this)
         Toast.makeText(this, "Enrolled with ${settings.baseUrl}", Toast.LENGTH_LONG).show()
     }

app/androidApp/src/main/kotlin/com/example/aiapp/MainScreen.kt

@@ -29,12 +29,10 @@ import androidx.lifecycle.repeatOnLifecycle
  * The app's root: one title, and four views of the backend behind it.
  *
  * These were four screens reached by four words in a row under the title, and the row was already
- * full -- the comment it replaced recorded that a fifth would have to go somewhere else. Tabs say
+ * full. Tabs say the same thing in less space and say one more thing besides: that these are places
- * the same thing in less space and say one more thing besides: that these are places to be rather
+ * to be rather than errands to run. Sessions, the machine's importable history, the models on it
- * than errands to run. Sessions, the machine's importable history, the models on it and the
+ * and the machines themselves are all *the same backend*, looked at four ways, and none is a step
- * machines themselves are all *the same backend*, looked at four ways, and none of them is a step
+ * down from another. Settings still is, which is why it stays a pushed screen with its own Back.
- * down from another. Settings still is a step down, which is why it stays a pushed screen and keeps
- * its own Back.
  */
 private enum class MainTab(val label: String) {
     Sessions("Sessions"),
@@ -61,17 +59,12 @@ fun MainScreen(
     //
     // What these four draw is a snapshot of a backend they are not connected to, so it is only as
     // fresh as the last answer -- and a *failed* answer is the one that outstays its welcome. A
-    // phone that was away while the tunnel was down, or that fetched before the network came up,
+    // phone that was away while the tunnel was down came back to "Couldn't reach the server"
-    // came back to "Couldn't reach the server" sitting at the top of a list the server would now
+    // sitting at the top of a list the server would now answer for perfectly well. A stale failure
-    // answer for perfectly well, and nothing took it off until somebody pressed Refresh. A stale
+    // is worse than a stale list: it is a claim about right now.
-    // failure is worse than a stale list: it is a claim about right now.
     //
     // Through the same token the Refresh button uses, so this is one instruction the tabs already
-    // understand rather than a second path into each of them -- which is also what makes it cover
+    // understand. Not on the first entry: the tab composing already asks.
-    // all four rather than the one the report came from.
-    //
-    // Not on the first entry: the tab composing already asks, and bumping here would make every
-    // cold start fetch twice.
     val lifecycleOwner = LocalLifecycleOwner.current
     LaunchedEffect(lifecycleOwner) {
         var opening = true
@@ -81,9 +74,8 @@ fun MainScreen(
         }
     }
 
-    // A tab the app put over the list has to step back to it rather than fall through to the
+    // A tab the app put over the list has to step back to it rather than fall through to the system
-    // system default, which closes the app -- that reads as a crash to somebody who only meant to
+    // default, which closes the app. Nested inside AppRoot's handler, so it wins while enabled.
-    // get back to their sessions. Nested inside AppRoot's handler, so it wins while it is enabled.
     BackHandler(enabled = tab != MainTab.Sessions) { tab = MainTab.Sessions }
 
     Column(Modifier.fillMaxSize()) {
@@ -98,20 +90,18 @@ fun MainScreen(
             )
             // Glyphs rather than the words they replaced: neither ever changes, both are read
             // faster than they are spelled, and together they take the width that let the title
-            // keep its own line. They sit on the title's row because they act on the whole
+            // keep its own line. They sit on the title's row because they act on the whole screen.
-            // screen -- everything below this row is one tab's business, and a control belongs
+            //
-            // with the thing it acts on.
+            // Flush against each other: a glyph button carries its own padding, so two side by side
-            // Flush against each other: a glyph button carries its own padding, so two of them
+            // already have two rings between their marks.
-            // side by side already have two rings between their marks and one ring plus this
-            // row's padding to the screen edge.
             Row {
                 GlyphButton(REFRESH_GLYPH, "Refresh", { refreshToken++ })
                 GlyphButton(SETTINGS_GLYPH, "Settings", onSettings)
             }
         }
-        // What is waiting to be attached, and what to do about it. Said here because the list
+        // What is waiting to be attached, and what to do about it. Said here because the list below
-        // below is where the choice is made, and a share that arrived with nothing on screen
+        // is where the choice is made, and a share that arrived with nothing on screen saying so
-        // saying so would read as a tap that did nothing.
+        // would read as a tap that did nothing.
         share?.let {
             Text(
                 it.summary() + " -- open the session it belongs in.",
@@ -127,8 +117,8 @@ fun MainScreen(
                         .padding(12.dp),
             )
         }
-        // Primary rather than the plain TabRow, which is deprecated in favour of the two that
+        // Primary rather than the plain TabRow, which is deprecated in favour of the two that say
-        // say where they sit: these are the app's top-level destinations.
+        // where they sit: these are the app's top-level destinations.
         PrimaryTabRow(selectedTabIndex = tab.ordinal) {
             MainTab.entries.forEach { entry ->
                 Tab(
@@ -139,10 +129,9 @@ fun MainScreen(
             }
         }
 
-        // Refreshing means "ask again about what I am looking at", so the button feeds the tab
+        // Refreshing means "ask again about what I am looking at", so the button feeds the tab that
-        // that is showing. The token from above means something else already changed what these
+        // is showing. The token from above means something else already changed what these show;
-        // show; the two are the same instruction to the tab below, so they are summed rather than
+        // the two are the same instruction, so they are summed rather than tracked apart.
-        // tracked apart -- either one moving moves the sum, which is all a tab watches.
         val token = reloadToken + refreshToken
         when (tab) {
             MainTab.Sessions ->

app/androidApp/src/main/kotlin/com/example/aiapp/Markdown.kt

@@ -69,13 +69,10 @@ import org.intellij.markdown.flavours.gfm.GFMTokenTypes
  *
  * [live] is the reply still arriving, and two things are different for it. Its parse is incremental
  * -- see [LiveParse] -- so a delta costs a parse of the block it landed in rather than of the whole
- * message. And its pieces get a layer each: when drawing is invalidated, only the piece that
+ * message. And its pieces get a layer each, so only the piece that changed is re-recorded. That is
- * changed is re-recorded instead of the whole reply, which is worth a great deal while every delta
+ * worth a great deal while every delta invalidates the message and worth nothing once it stops
- * invalidates the message and a finished one can be twenty-five screens tall. It is worth nothing
+ * changing -- and it is not free: each layer is a layout node and a display list held for the life
- * once the message stops changing -- measured on a Pixel 9 Pro XL, whole rows were re-recorded 65
+ * of the row, and live node count is what the transcript's per-frame cost scales with.
- * times in fifty seconds of reading -- and it is not free: each layer is a layout node and a
- * display list held for the life of the row, and live node count is what the per-frame cost of the
- * transcript scales with.
  */
 @Composable
 fun MarkdownText(
@@ -92,8 +89,8 @@ fun MarkdownText(
         var previousSegment: Segment? = null
         segments.forEachIndexed { at, segment ->
             val nextContinues = segments.getOrNull(at + 1)?.continues == true
-            // Only the tail is still being written; a frozen segment is finished text that
+            // Only the tail is still being written; a frozen segment is finished text that happens
-            // happens to sit in a live reply, and it takes its colours now. See [MarkdownRoot].
+            // to sit in a live reply, and it takes its colours now.
             MarkdownRoot(segment.parse, replies, streaming = live && at == segments.lastIndex) {
                 segment.pieces.forEachIndexed { index, piece ->
                     val gap =
@@ -103,9 +100,9 @@ fun MarkdownText(
                                 if (segment.continues) 0.dp else BLOCK_SPACING
                             else -> gapBefore(previous, piece)
                         }
-                    // Keyed by where the piece starts in the message rather than by its position
+                    // Keyed by where the piece starts in the message rather than by its position in
-                    // in this column, so a delta landing in the last block leaves every other
+                    // this column, so a delta landing in the last block leaves every other piece's
-                    // piece's composition alone -- and a block keeps its key when it freezes.
+                    // composition alone -- and a block keeps its key when it freezes.
                     key(segment.start, piece) {
                         MarkdownPiece(
                             segment.parse,
@@ -137,8 +134,7 @@ fun MarkdownText(
  * A stretch of a message with a parse of its own: the whole of a settled message, or one block, the
  * finished items of one list, or the unfinished tail of a live one. [start] is where [text] begins
  * in the message. [continues] says the first piece is an item of the list the segment before it
- * ended with, so the two draw as one list: no block gap between them, and neither the item above
+ * ended with, so the two draw as one list.
- * the seam nor the one below it takes the padding of a list's edge.
  */
 private class Segment(
     val text: String,
@@ -154,14 +150,11 @@ private class Segment(
  *
  * The first parse has to be inline. The renderer's own asynchronous path draws an empty loading
  * slot until its result arrives, so a row is measured at nothing before it is measured at its real
- * height, and the transcript above it collapses and springs back. Seen with five replies on screen
+ * height, and the transcript above it collapses and springs back -- seen with five replies on
- * at once, every one of them blank, the whole conversation shrunk to fit a single screen; a moment
+ * screen at once, the whole conversation shrunk to fit a single screen.
- * later it was all there again. That is the "skipping up and down" this list must never do.
  *
  * Every parse after the first is off the composing thread, and the row keeps drawing the parse it
- * already has until the new one lands, so there is never a frame without a height. What is on
+ * already has until the new one lands, so there is never a frame without a height.
- * screen is always a real prefix of the reply rather than a guess at it; it is simply one parse
- * behind.
  */
 @Composable
 private fun liveSegments(text: String): List<Segment> {
@@ -187,24 +180,18 @@ private fun liveSegments(text: String): List<Segment> {
  * Reparsing the whole message per delta was fine for a short reply and not for a long one: a
  * twenty-five-screen reply parses in tens of milliseconds, hundreds of times, and although that ran
  * off the composing thread it was every core busy while the frame's own thread waited for one.
- * Markdown's blocks make the cut safe: a top-level block that another block has started *after* is
- * finished -- nothing appended later can reach back into it, since a paragraph ends at the blank
- * line or the block that interrupts it, a fence at its closing fence, a list at the first line that
- * is neither an item nor indented under one. So every block but the last is [frozen] with the parse
- * that finished it, and only the tail -- the last block and whatever has arrived since -- is parsed
- * again.
  *
- * A list is cut once more, at its last item, by the same reasoning one level down: an item is
+ * Markdown's blocks make the cut safe: a top-level block that another block has started *after* is
- * finished once the next item has begun, since a line can only continue the item it is indented
+ * finished -- nothing appended later can reach back into it. So every block but the last is
- * under or start a new one. Without this a reply that is one long list -- forty sources -- parsed
+ * [frozen] with the parse that finished it, and only the tail is parsed again.
- * the whole list per delta, and a list streams as forty paragraphs would. The item the cut lands on
+ *
- * has to have begun in earnest: a bare `-` is an empty item now and the first character of a
+ * A list is cut once more, at its last item, by the same reasoning one level down. Without this a
- * paragraph line once `-x` arrives, and cutting on it would draw that line as a new item.
+ * reply that is one long list -- forty sources -- parsed the whole list per delta. The item the cut
+ * lands on has to have begun in earnest: a bare `-` is an empty item now and the first character of
+ * a paragraph line once `-x` arrives.
  *
  * What the cut gives up is one thing: a reference definition arriving later than a link that uses
- * it, since the frozen block's parse never sees it. The link draws as its brackets until the reply
+ * it. The link draws as its brackets until the reply settles and is parsed whole by [warm].
- * settles and is parsed whole by [warm], which is the same moment every other transient of
- * streaming is put right.
  */
 private class LiveParse(
     val text: String,
@@ -217,8 +204,8 @@ private class LiveParse(
         get() = frozen + tail
 
     fun advanceTo(next: String): LiveParse {
-        // Anything but an append to what was frozen -- a message replaced, a stream reset --
+        // Anything but an append to what was frozen -- a message replaced, a stream reset -- starts
-        // starts over.
+        // over.
         if (!next.regionMatches(0, text, 0, consumed)) return whole(next)
         val tailText = next.substring(consumed)
         val parse = parseMarkdown(tailText)
@@ -264,8 +251,7 @@ private class LiveParse(
 
     /**
      * The piece of the tail still being written: the last item of a list of several, or the first
-     * piece of the last block when there is more than one block. Null when nothing before it is
+     * piece of the last block when there is more than one. Null when nothing before it is finished.
-     * finished, so the tail stays whole.
      */
     private fun openPiece(parse: State.Success, all: List<Piece>): Piece? {
         val last = all.lastOrNull() ?: return null
@@ -315,28 +301,24 @@ fun MarkdownPiece(
  * The renderer's own environment -- its colours, type scale, dimensions, component table and
  * reference links -- around whatever draws pieces of [parse].
  *
- * The parsing is the library's. Markdown is somebody else's specification, and a hand-written
+ * The parsing is the library's: markdown is somebody else's specification, and a hand-written
  * parser would get the edge cases wrong one case at a time. So is the environment: the element
  * composables its dispatch reaches read these locals, and providing them once here is what lets a
  * piece be drawn anywhere -- in a message's column, or as one item of the transcript list.
- * Everything below this is the mapping onto the app's palette and type scale.
  *
  * The locals are provided directly rather than through the renderer's `Markdown()` composable,
- * which was the last of its composables on the hot path and was here only to provide them. What
+ * which was the last of its composables on the hot path and was here only to provide them. So
- * that buys is that nothing between a piece and the screen is the library's but the leaf
+ * nothing between a piece and the screen is the library's but the leaf composables named in the
- * composables named in the component table, so a different parser could stand behind [State]
+ * component table.
- * without the renderer's entry point being involved.
  *
- * Colours come from the theme rather than from the renderer's defaults, so code, links and rules
+ * Colours come from the theme rather than the renderer's defaults. Nothing here picks one of its
- * are the same Catppuccin values the rest of the app uses. Nothing here picks a colour of its own.
+ * own.
  *
  * [streaming] says this parse is the part of a reply still being written, which only the fences
- * care about: lexing is proportional to how much code there is, and a fence still arriving is
+ * care about: lexing is proportional to how much code there is. Measured streaming a two-hundred-
- * re-lexed at every delta on the composing thread. Measured streaming a two-hundred-line Kotlin
+ * line Kotlin fence: **13.7 seconds** of lexing across the turn, 211 of them, the worst 177ms --
- * fence: **13.7 seconds** of lexing across the turn, 211 of them, the worst 177ms -- for colours on
+ * for colours on text being replaced as fast as they were computed. So a fence still being written
- * text that was being replaced as fast as they were computed. So a fence still being written is
+ * is drawn plain and takes its colours when the block freezes.
- * drawn plain and takes its colours when the block freezes, which is the same bargain [LiveParse]
- * already makes for a reference link defined at the foot of a message.
  */
 @Composable
 private fun MarkdownRoot(
@@ -354,45 +336,40 @@ private fun MarkdownRoot(
     CompositionLocalProvider(
         LocalReferenceLinkHandler provides parse.referenceLinkHandler,
         LocalMarkdownPadding provides markdownPadding(),
-        // Read by the renderer's own text composable, which no paragraph reaches any more, and
+        // Read by the renderer's own text composable, which no paragraph reaches any more, and by
-        // by its checkbox. Provided so a path that does reach them draws no image rather than
+        // its checkbox. Provided so a path that does reach them draws no image rather than failing
-        // failing to compose.
+        // to compose.
         LocalImageTransformer provides remember { NoOpImageTransformerImpl() },
         LocalMarkdownAnimations provides markdownAnimations(),
         LocalMarkdownColors provides
             markdownColor(
                 text = MaterialTheme.colorScheme.onSurface,
                 dividerColor = MaterialTheme.colorScheme.outlineVariant,
-                // The dark surface every verbatim thing in this app sits on -- see [rawSurface],
+                // The dark surface every verbatim thing in this app sits on -- and the tool call
-                // and the tool call above this reply, which now matches. `surfaceVariant` was
+                // above this reply, which now matches. `surfaceVariant` was exactly a card's own
-                // exactly a card's own fill, so a fenced block inside a tool call had no
+                // fill, so a fenced block inside a tool call had no background at all.
-                // background at all and one in a reply read as a step *up* out of the page.
                 codeBackground = rawSurface,
                 // The same colour. Not drawn by the renderer as a span background but by
-                // [LinkedText] behind the text, so a selection lands on top of it as it does on a
+                // [LinkedText] behind the text, so a selection lands on top of it -- see
-                // fenced block -- see `appendCodeChip`.
+                // `appendCodeChip`.
                 inlineCodeBackground = rawSurface,
-                // The same tint a code block gets, rather than the renderer's 2%-alpha default:
+                // The same tint a code block gets, rather than the renderer's 2%-alpha default: two
-                // two adjacent tints that differ by a fiftieth read as one flat block on a phone,
+                // adjacent tints that differ by a fiftieth read as one flat block on a phone.
-                // so the table would have had a border-less grid and nothing saying where it began.
                 tableBackground = MaterialTheme.colorScheme.surfaceVariant,
             ),
         LocalMarkdownTypography provides
             markdownTypography(
                 // A ladder that starts near the body text and descends, because these are headings
                 // inside a chat message rather than the top of a document. The renderer's defaults
-                // are the Material *display* styles -- `#` came out at 57sp and `##` at 45sp, which
+                // are the Material *display* styles -- `#` came out at 57sp, bigger than this app's
-                // is bigger than this app's own screen titles and reads as the reply shouting.
+                // own screen titles. Every step is a different size, so two levels of nesting never
-                //
+                // draw the same.
-                // Every step is a different size, so two levels of nesting never draw the same:
-                // one clear step per level is the whole job of a heading.
                 h1 = MaterialTheme.typography.headlineSmall,
                 h2 = MaterialTheme.typography.titleLarge,
                 h3 = MaterialTheme.typography.titleMedium,
                 h4 = MaterialTheme.typography.titleSmall,
                 h5 = MaterialTheme.typography.labelMedium,
                 h6 = MaterialTheme.typography.labelSmall,
-                // Body text at the size everything else in the transcript uses.
                 text = body,
                 paragraph = body,
                 ordered = body,
@@ -400,16 +377,10 @@ private fun MarkdownRoot(
                 list = body,
                 table = body,
                 // Code in a monospace face, in the ordinary text colour. The face and the tinted
-                // background are what say "this is code"; colour is not, and it used to be green
+                // background are what say "this is code"; colour is not, and it used to be green --
-                // -- the palette's colour for a *literal*. A block of code is not a literal, it
+                // the palette's colour for a *literal*. A block of code is not a literal, and
-                // is text that happens to be code, and painting all of it green said the whole
+                // painting all of it green said the whole block was one. Where a literal really
-                // block was one. Where a literal really does appear inside code, the thing that
+                // does appear inside code, what should colour it is a syntax highlighter.
-                // should colour it is a syntax highlighter looking at the code, which is exactly
-                // what a tool call's input already gets from `catppuccinSyntax`.
-                //
-                // The colour rides on the style here rather than in `markdownColor`, which
-                // stopped carrying `codeText`/`inlineCodeText`/`linkText` when the renderer moved
-                // them onto the typography.
                 code =
                     MaterialTheme.typography.bodyMedium.copy(
                         fontFamily = FontFamily.Monospace,
@@ -436,31 +407,26 @@ private fun MarkdownRoot(
         LocalMarkdownDimens provides
             markdownDimens(
                 // Half the renderer's 16dp. Padding is charged on both sides of every cell, so at
-                // the default a fifth of the narrowest column went on space rather than on words
+                // the default a fifth of the narrowest column went on space rather than on words.
-                // -- and the narrowest column is where the wrapping below has the least room.
                 tableCellPadding = 8.dp,
                 // What a column narrows to before the table starts scrolling sideways instead. It
                 // is the floor, not the width: a table with room to spare spreads across it.
                 //
                 // Down from the renderer's 160dp, and the number is a measurement rather than a
                 // taste. A phone is about 410-450dp wide and a card takes some of that, so 160dp
-                // makes even a three-column table -- the commonest shape there is -- scroll, while
+                // makes even a three-column table scroll, while 136dp fits three across the phone
-                // 136dp fits three across the phone this app is read on. Four and up still scroll,
+                // this app is read on. Four and up still scroll, which is the right answer for
-                // which is the right answer for genuinely too many columns: squeezing six columns
+                // genuinely too many columns. This is the widest minimum that keeps three on
-                // into a phone would give every cell one word per line.
+                // screen.
-                //
-                // Narrower would fit more, and stop being readable. This is the widest minimum
-                // that keeps three columns on screen, which is the trade the number is making.
                 tableCellWidth = 136.dp,
             ),
         LocalMarkdownComponents provides
             markdownComponents(
                 // The m3 renderer's own default, restored: supplying `components` at all replaces
-                // the whole set, and this is the only member of it the Material layer overrides.
+                // the whole set, and this is the only member the Material layer overrides.
                 checkbox = { MarkdownCheckBox(it.content, it.node, it.typography.text) },
                 // Everything that draws a run of text, so a link is a span rather than a node --
-                // see [LinkedText]. Setext headings take the same styles as `#` and `##`, which
+                // see [LinkedText]. Setext headings take the same styles as `#` and `##`.
-                // is the renderer's own pairing.
                 text = { LinkedText(it, it.typography.text) },
                 paragraph = { LinkedText(it, it.typography.paragraph) },
                 heading1 = { LinkedHeading(it, it.typography.h1) },
@@ -471,8 +437,8 @@ private fun MarkdownRoot(
                 heading6 = { LinkedHeading(it, it.typography.h6) },
                 setextHeading1 = { LinkedHeading(it, it.typography.h1) },
                 setextHeading2 = { LinkedHeading(it, it.typography.h2) },
-                // Lists are ours wherever the renderer's dispatch meets one -- inside a quote --
+                // Lists are ours wherever the renderer's dispatch meets one -- inside a quote -- so
-                // so they draw like the top-level ones the transcript cuts into items.
+                // they draw like the top-level ones the transcript cuts into items.
                 orderedList = { MarkdownList(it.content, it.node, it.listDepth) },
                 unorderedList = { MarkdownList(it.content, it.node, it.listDepth) },
                 table = { LinkedTable(it.content, it.node, it.typography.table) },
@@ -491,14 +457,12 @@ private fun MarkdownRoot(
 /**
  * A table: its rows, on the renderer's tinted, rounded background, as wide as its columns need.
  *
- * Each column has a floor ([markdownDimens]'s `tableCellWidth`), so the table is at least
+ * Each column has a floor, so the table is at least columns-times-floor wide; narrower than the
- * columns-times-floor wide; narrower than the room it has, it spreads to fill it, and wider, it
+ * room it has, it spreads to fill it, and wider, it scrolls sideways rather than squeezing. The
- * scrolls sideways rather than squeezing. The renderer decided that with a `BoxWithConstraints`,
+ * renderer decided that with a `BoxWithConstraints`, which is a subcomposition; here it is one
- * which is a subcomposition; here it is one layout modifier, and the trick is where it sits.
+ * layout modifier. `fillMaxWidth` fixes the minimum width to the room available, the horizontal
- * `fillMaxWidth` fixes the minimum width to the room available, the horizontal scroll passes that
+ * scroll passes that minimum through while lifting the maximum to unbounded, and the modifier after
- * minimum through to its content while lifting the maximum to unbounded, and the modifier after it
+ * it reads the minimum back and sizes the rows to the larger of that and the floor.
- * reads the minimum back as the room and sizes the rows to the larger of that and the floor. The
- * scroll then has exactly the overflow to scroll, which is none when the table fits.
  */
 @Composable
 private fun LinkedTable(content: String, node: ASTNode, style: TextStyle) {
@@ -539,19 +503,15 @@ private fun LinkedTable(content: String, node: ASTNode, style: TextStyle) {
  * One row of a table -- the header when [rowIndex] is zero -- with every cell a [LinkedText].
  *
  * The renderer's own rows draw each cell at `maxLines = 1` with an ellipsis, which on a phone means
- * most of a table is simply not readable: anything past about twenty characters ends in "..." with
+ * most of a table is simply not readable: an elided cell looks like a short one, so a table of
- * no way to see the rest, and an elided cell looks like a short one, so a table of measurements
+ * measurements reads as a table of plausible shorter measurements. And they draw a link in a cell
- * reads as a table of plausible shorter measurements. And they draw a link in a cell as its own
+ * as its own layout node, the cost [LinkedText] exists to avoid.
- * layout node, the cost [LinkedText] exists to avoid.
  *
  * So: as many lines as the cell needs, cells aligned to the top of the row, because a two-line cell
- * beside a one-line one centred the short one against the middle of the tall one and lost the line
+ * beside a one-line one centred the short one against the middle of the tall one. What the wrapping
- * the reader was reading across. What the wrapping does *not* do is make a wide table fit;
+ * does *not* do is make a wide table fit; [LinkedTable] scrolls it instead.
- * [LinkedTable] scrolls it instead, which is the right answer for too many columns -- wrapping a
- * six-column table into the width of a phone would give every cell one word per line.
  *
- * The semantics are the renderer's: each cell is an item of the table's collection, and a header
+ * The semantics are the renderer's: each cell is an item of the table's collection.
- * cell is a heading.
  */
 @Composable
 private fun LinkedTableRow(content: String, row: ASTNode, style: TextStyle, rowIndex: Int) {
@@ -587,19 +547,14 @@ private fun LinkedTableRow(content: String, row: ASTNode, style: TextStyle, rowI
  * Parsing is the expensive half of drawing a reply, and it is expensive in proportion to how much
  * was written. Measured against a real Claude Code transcript on the emulator, one message took
  * **51ms** and several took 10-25ms, against 4.6ms for the short synthetic replies this was first
- * tuned on -- so a page of history landing composed several rows that each stalled the frame they
+ * tuned on -- so a page of history landing composed several rows that each stalled the frame.
- * appeared in. That is the lag when a block loads.
  *
- * Nothing here changes what a row does when it has no answer waiting: it parses inline, on the
+ * Nothing here changes what a row does when it has no answer waiting: it parses inline, because a
- * composing thread, because a row measured at nothing before it is measured at its real height
+ * row measured at nothing before its real height collapses the transcript above it. The point is
- * collapses the transcript above it. The point is only that by the time the reader scrolls to a
+ * only that by the time the reader scrolls to a row, the answer is usually already made.
- * row, the answer is usually already made -- [warm] runs on a background thread as each page of
- * history arrives, which is seconds before anybody reaches the rows it brought.
  *
  * A miss is not stored, and that is what bounds this: the map holds one entry per message a page
- * warmed and nothing else, so a reply still streaming cannot fill it with hundreds of copies of
+ * warmed, so a reply still streaming cannot fill it with hundreds of copies of itself.
- * itself on the way to being finished. It is dropped with the screen, and emptied by the stream
- * reset that drops the rows it describes.
  */
 @Stable
 class ParsedReplies {
@@ -607,14 +562,13 @@ class ParsedReplies {
 
     /**
      * How each message divides into pieces, cached beside its parse: [transcriptUnits] asks per
-     * fold, and walking the tree again each time is proportional to the message where a lookup is
+     * fold, and walking the tree again each time is proportional to the message.
-     * proportional to nothing.
      */
     private val pieces = ConcurrentHashMap<String, List<Piece>>()
 
     /**
-     * How each message divides into prose and memory notes, cached for the same reason as
+     * How each message divides into prose and memory notes, cached for the same reason: the regex
-     * [piecesOf]: the regex scan behind [messageParts] is proportional to the message.
+     * scan behind [messageParts] is proportional to the message.
      */
     private val parts = ConcurrentHashMap<String, List<MessagePart>>()
 
@@ -627,7 +581,7 @@ class ParsedReplies {
      * much code was written -- a two-hundred-line Kotlin fence measured 174ms on the emulator --
      * and a lazy list drops the composition of a block that scrolls away, so a `remember` inside
      * the fence paid that again every time the reader came back to it. Six times in one scroll,
-     * measured. [warm] fills this off the drawing thread before the row is reached.
+     * measured.
      */
     private val highlights = ConcurrentHashMap<String, AnnotatedString>()
 
@@ -649,11 +603,10 @@ class ParsedReplies {
      * Whether [warm] has made everything drawing [text] as pieces will look up.
      *
      * What the flatten asks before drawing a reply that way. Cutting costs a parse of the whole
-     * message and the flatten runs on the composing thread -- so a reply not marked yet stays
+     * message and the flatten runs on the composing thread, so a reply not marked yet stays whole
-     * whole, drawing the parse it already has, until the screen has warmed it and re-flattens. An
+     * until the screen has warmed it. An explicit mark rather than a peek into the parse cache,
-     * explicit mark rather than a peek into the parse cache, because a message with memory notes is
+     * because a message with memory notes is warmed as its *parts*: nothing ever parses its full
-     * warmed as its *parts*: nothing ever parses its full text, and inferring readiness from the
+     * text, and inferring readiness from the cache left exactly that message unsplittable forever.
-     * cache left exactly that message unsplittable forever, re-warmed on every fold.
      */
     fun splitReady(text: String): Boolean = text in ready
 
@@ -668,9 +621,8 @@ class ParsedReplies {
         }
 
     /**
-     * [code] coloured for [language] -- the answer made ahead, or one made now.
+     * [code] coloured for [language] -- the answer made ahead, or one made now. The key carries the
-     *
+     * language, because the same code lexes differently under two of them.
-     * The key carries the language, because the same code lexes differently under two of them.
      */
     fun highlighted(code: String, language: Language?): AnnotatedString =
         if (language == null) AnnotatedString(code)
@@ -686,9 +638,9 @@ class ParsedReplies {
      *
      * Suspending, and yielding between messages, because "off the composing thread" is not the same
      * as "free". A page of history arrives as hundreds of parses at once -- 1.5 seconds of them in
-     * a twelve second scroll, measured on a Pixel 9 Pro XL -- and on the default dispatcher that is
+     * a twelve second scroll on a Pixel 9 Pro XL -- and on the default dispatcher that is every
-     * every core busy, with the frame's own thread waiting for one. That showed up as 21ms of
+     * core busy, with the frame's own thread waiting for one: 21ms of `waited` at the 90th
-     * `waited` at the 90th percentile: the frame could not start, rather than taking too long.
+     * percentile.
      */
     suspend fun warm(texts: List<String>) {
         texts.forEach { text ->
@@ -697,9 +649,8 @@ class ParsedReplies {
                     DebugStats.timed("markdown warmed") { parseMarkdown(it) }
                 }
             // The fences too, and here rather than in a pass of its own: they are found in the
-            // parse this just made, and lexing one is the same kind of cost as parsing the
+            // parse this just made, and lexing one is the same kind of cost as parsing the message
-            // message it is in -- proportional to what was written, and charged to the frame
+            // it is in.
-            // that first draws it if nobody paid it earlier.
             fences(parse).forEach { (code, language) -> highlighted(code, language) }
         }
     }

app/androidApp/src/main/kotlin/com/example/aiapp/MarkdownLinks.kt

@@ -44,27 +44,22 @@ import org.intellij.markdown.flavours.gfm.GFMTokenTypes
  *
  * Compose turns every `LinkAnnotation` in a text into a layout node: a clipped, focusable,
  * hoverable, clickable box laid out against the glyphs, with its outline recomputed from the text
- * layout. A paragraph of eight links is therefore nine nodes, and the renderer emits one of those
+ * layout. A paragraph of eight links is therefore nine nodes, and the renderer emits one annotation
- * annotations per link. Measured on the emulator against the same paragraphs with each link
+ * per link. Measured on the emulator against the same paragraphs with each link replaced by its
- * replaced by its label and address as plain words -- *more* text, the same gestures -- the linked
+ * label and address as plain words -- *more* text, the same gestures -- the linked version cost
- * version cost five times the worst measure (26.3ms against 5.2ms) and 1.7x the place time. On a
+ * five times the worst measure (26.3ms against 5.2ms) and 1.7x the place time.
- * Pixel 9 Pro XL that was the bump at the list of sources in a reply, and nowhere else in it.
  *
  * Here a link is the link colour and underline, a string annotation carrying its address, and one
  * tap detector for the whole text that asks the layout which character was under the finger. What
  * that gives up is a link being its own accessibility node with a pressed state; the app's link
  * style never defined a pressed style, so nothing visible changes.
  *
- * Every block the renderer dispatches through its component table comes here, which includes the
+ * Every block the renderer dispatches through its component table comes here, and so does every
- * paragraphs inside lists, quotes and alerts, and so does every table cell through
+ * table cell. Reference-style links are the one kind still drawn the renderer's way.
- * [LinkedTableRow]. Reference-style links are the one kind still drawn the renderer's way; it
- * resolves those against its definitions.
  *
  * An image is a link too, carrying its alt text. The app has no image loader and the renderer's
  * transformer was the no-op one, so an image in a reply drew as nothing at all -- a hole where the
- * model put something, with no sign of what fell out. The link says what was there and where, and
+ * model put something. The link says what was there and where, and opens it.
- * opens it. It also means no paragraph needs the renderer's own text composable, which existed to
- * place inline images and charged every paragraph for the possibility.
  */
 @Composable
 fun LinkedText(model: MarkdownComponentModel, style: TextStyle) {
@@ -74,8 +69,7 @@ fun LinkedText(model: MarkdownComponentModel, style: TextStyle) {
 /**
  * A heading. Its words are a child of the heading node -- `ATX_CONTENT` after the `#`s, or
  * `SETEXT_CONTENT` above the underline -- and the inline builder draws nothing for a node type it
- * does not know, so handed the heading node itself it draws an empty line. Which is what this did
+ * does not know, so handed the heading node itself it draws an empty line.
- * for a week.
  */
 @Composable
 fun LinkedHeading(model: MarkdownComponentModel, style: TextStyle) {
@@ -113,18 +107,18 @@ fun LinkedText(content: String, node: ASTNode, style: TextStyle, modifier: Modif
     BasicText(
         text = text,
         modifier =
-            // A tap here is either a link or the card's; see [LocalMarkdownTap] for why the
+            // A tap here is either a link or the card's; see [LocalMarkdownTap] for why the second
-            // second one has to be answered from inside the text rather than left to the card.
+            // one has to be answered from inside the text rather than left to the card.
             modifier.then(chipFill).pointerInput(text, onPlainTap) {
                 awaitEachGesture {
                     // Unconsumed is not required: something outside may already be tracking this
                     // press, and it is still the press that may land on a link.
                     awaitFirstDown(requireUnconsumed = false)
-                    // A tap and nothing else. Null when the gesture became something somebody
+                    // A tap and nothing else. Null when the gesture became somebody else's -- a
-                    // else's -- a scroll, or a press held past the long-press timeout, which is
+                    // scroll, or a press held past the long-press timeout, which is how a selection
-                    // how a selection starts. The timeout is the load-bearing half: without it a
+                    // starts. The timeout is the load-bearing half: without it a press held for a
-                    // press held for a second and released was still an up with nothing consumed,
+                    // second and released was still an up with nothing consumed, so holding a peer
-                    // so holding a peer message to select from it shut the card instead.
+                    // message to select from it shut the card instead.
                     val up =
                         withTimeoutOrNull(viewConfiguration.longPressTimeoutMillis) {
                             waitForUpOrCancellation()
@@ -156,27 +150,24 @@ fun LinkedText(content: String, node: ASTNode, style: TextStyle, modifier: Modif
  * usually -- or null where a plain tap means nothing.
  *
  * A composition local because there is nowhere else to put it. The paragraphs of a message are
- * composed by the renderer's own dispatch out of its component table, so nothing between a card and
+ * composed by the renderer's own dispatch, so nothing between a card and the text inside it is ours
- * the text inside it is ours to pass a parameter through; the renderer already hands its colours,
+ * to pass a parameter through.
- * its typography and its components down the same way.
  *
  * It exists because a pointer-input node over the glyphs takes the tap and the card's own click
- * handler never sees it. Measured on the emulator against an opened peer message: with a handler on
+ * handler never sees it. Measured against an opened peer message: with a handler on the text --
- * the text -- consuming or not -- a tap on its words did nothing at all, and with the handler
+ * consuming or not -- a tap on its words did nothing at all, and with the handler removed the same
- * removed entirely the same tap shut the card. So a card whose body is markdown cannot be shut by
+ * tap shut the card. So a card whose body is markdown cannot be shut by pressing its words unless
- * pressing its words unless the words do the shutting, and "nothing happens when I press it" is
+ * the words do the shutting.
- * indistinguishable from a card that has stopped working.
  *
- * Provided as a value that outlives a recomposition (see [rememberMarkdownTap]), since a fresh
+ * Provided as a value that outlives a recomposition, since a fresh lambda per composition would
- * lambda per composition would invalidate every paragraph reading it.
+ * invalidate every paragraph reading it.
  */
 val LocalMarkdownTap = compositionLocalOf<(() -> Unit)?> { null }
 
 /**
- * [onTap] as a stable value to provide for [LocalMarkdownTap].
+ * [onTap] as a stable value to provide for [LocalMarkdownTap]. The identity stays put while the
- *
+ * behaviour follows the latest [onTap], which is what keeps providing it from invalidating the text
- * The identity stays put while the behaviour follows the latest [onTap], which is what keeps
+ * under it on every recomposition of the card.
- * providing it from invalidating the text under it on every recomposition of the card.
  */
 @Composable
 fun rememberMarkdownTap(onTap: () -> Unit): () -> Unit {
@@ -212,9 +203,8 @@ private const val LINK_URL = "url"
  * The chip's fill is drawn by [LinkedText] from the layout instead, behind the text. A span's
  * background is part of the text's own drawing, and the text node draws the selection first and the
  * glyphs over it, so a chip painted as a span background covered the selection: selecting a
- * sentence highlighted every word of it except the ones in backticks. Anything drawn by a modifier
+ * sentence highlighted every word except the ones in backticks. Anything drawn by a modifier on the
- * on the text is under both, which is where a fenced block's box already is and why one of those
+ * text is under both, which is where a fenced block's box already is.
- * always looked right. The [CODE_CHIP] annotation is what says where the fill goes.
  */
 private fun appendCodeChip(
     builder: AnnotatedString.Builder,
@@ -242,13 +232,11 @@ private const val CODE_CHIP = "code"
  * Not `getPathForRange`, which is the geometry of a *selection* and runs to the right edge of every
  * line but the last, so a chip whose code wrapped left a full-width empty box behind on the line
  * above. Each line is taken as far as `visibleEnd`, which is where that line's own trailing space
- * stops being drawn: the same rule the selection rectangle obeys, so the two agree rather than the
+ * stops being drawn -- the same rule the selection rectangle obeys, so the two agree.
- * chip sticking a space out past the end of a selected line. It is also what leaves nothing behind
- * when the only thing to reach a line is the space a chip is padded with.
  *
  * A run's extent is taken from the boxes of its first and last characters, which is exact while a
  * line reads in one direction; mixed directions inside a code span would draw one box across the
- * whole run rather than one per direction, and code spans are code.
+ * whole run, and code spans are code.
  */
 private fun TextLayoutResult.chipRects(start: Int, end: Int): List<Rect> {
     val rects = mutableListOf<Rect>()

app/androidApp/src/main/kotlin/com/example/aiapp/MarkdownPieces.kt

@@ -34,22 +34,18 @@ import org.intellij.markdown.flavours.gfm.GFMTokenTypes
  *
  * The point is the draw phase and the lazy list. A reply's display list holds every glyph of it and
  * is re-recorded whenever drawing is invalidated, so one long message costs as much to draw as a
- * hundred short ones; and the list composes an item whole in the frame it scrolls into, so an item
+ * hundred short ones; and the list composes an item whole in the frame it scrolls into. Measured on
- * has to be bounded for the worst frame to be. Measured on a Pixel 9 Pro XL, the tallest row still
+ * a Pixel 9 Pro XL, the tallest row still being drawn was 36,982px -- twenty-five screens in one
- * being drawn was 36,982px, twenty-five screens in one message. A piece is a paragraph, a fence, a
+ * message. A piece is a paragraph, a fence, a table, one bullet: bounded, so both costs are.
- * table, one bullet: bounded, so both costs are.
  *
- * Cut where the parser says the blocks are, which is the whole reason this is safe: a fence, a
+ * Cut where the parser says the blocks are, which is what makes it safe: a fence, a table and a
- * table and a nested list are each one node whatever is inside them, so nothing is ever split down
+ * nested list are each one node whatever is inside them. A list is the one block that is not
- * the middle. A list is the one block that is not bounded -- a reply's list of sources can be forty
+ * bounded -- a reply's list of sources can be forty items -- so it is cut once more, into its
- * items -- so it is cut once more, into its items, and a nested list stays inside the item that
+ * items.
- * holds it.
  *
- * A piece is an *address* into the message's one parse ([block] indexes the root's children, [item]
+ * A piece is an *address* into the message's one parse rather than a substring of it. Every piece
- * the list items of that child) rather than a substring of the message. Every piece of a message is
+ * is drawn from the same tree, so a message is parsed once however many pieces it is drawn as, and
- * drawn from the same tree, so a message is parsed once however many pieces it is drawn as, and a
+ * a reference definition at its foot still resolves the links above it.
- * reference definition at its foot still resolves the links above it -- the two costs of cutting a
- * message into strings and parsing each on its own.
  */
 @Immutable
 data class Piece(val block: Int, val item: Int = WHOLE_BLOCK) {
@@ -59,8 +55,7 @@ data class Piece(val block: Int, val item: Int = WHOLE_BLOCK) {
 }
 
 /**
- * The pieces of [parse], in reading order. Blank nodes between blocks -- the parser keeps the
+ * The pieces of [parse], in reading order. Blank nodes between blocks are not pieces.
- * newlines -- are not pieces.
  *
  * A parse that failed yields one piece, so [MarkdownPiece] can still say what the message was: a
  * message that drew as nothing would be a hole in the transcript with no sign of what fell out.
@@ -90,17 +85,15 @@ fun gapBefore(previous: Piece?, piece: Piece): Dp =
 val BLOCK_SPACING: Dp = 6.dp
 
 /**
- * [piece] of [parse], drawn. Must be inside [MarkdownRoot] for the parse, which is what carries the
+ * [piece] of [parse], drawn. Must be inside [MarkdownRoot] for the parse, which carries the theme,
- * theme, the components and the reference links to the renderer's element composables.
+ * the components and the reference links to the renderer's element composables.
  *
- * A whole block goes to the renderer's own dispatch with this app's component table, so a paragraph
+ * A whole block goes to the renderer's own dispatch with this app's component table. Only the list
- * or heading is a [LinkedText], a table is [LinkedTableRow]s, and a nested list comes back here
+ * item is drawn directly, because a list item is the one piece the renderer has no element for.
- * through [MarkdownList]. Only the list item is drawn directly, because a list item is the one
- * piece the renderer has no element for.
  *
- * [continuesList] and [listContinues] are for a list cut across the segments of a live reply (see
+ * [continuesList] and [listContinues] are for a list cut across the segments of a live reply: an
- * `LiveParse`): an item that is the first or last of its own parse but not of the list the reader
+ * item that is the first or last of its own parse but not of the list the reader sees keeps an
- * sees keeps an inner item's padding, so nothing moves when the seam between segments does.
+ * inner item's padding, so nothing moves when the seam between segments does.
  */
 @Composable
 fun MarkdownPiece(
@@ -112,8 +105,8 @@ fun MarkdownPiece(
     listContinues: Boolean = false,
 ) {
     if (parse !is State.Success) {
-        // The parser threw. Nothing else in the app has seen this happen; if it does, the words
+        // The parser threw. Nothing else in the app has seen this happen; if it does, the words are
-        // are still worth more than a blank.
+        // still worth more than a blank.
         Text(text, modifier, style = MaterialTheme.typography.bodyLarge)
         return
     }
@@ -144,8 +137,7 @@ fun MarkdownPiece(
 
 /**
  * A whole list, for the places the renderer's dispatch reaches one it cannot hand to a piece: a
- * list inside a quote, and the nested lists an item holds. Top-level lists never come here; they
+ * list inside a quote, and the nested lists an item holds. Top-level lists never come here.
- * are drawn an item at a time as pieces.
  */
 @Composable
 fun MarkdownList(content: String, list: ASTNode, depth: Int, modifier: Modifier = Modifier) {
@@ -170,9 +162,8 @@ fun MarkdownList(content: String, list: ASTNode, depth: Int, modifier: Modifier
  * list drawn as pieces looks exactly like one drawn whole. The list's own padding goes on its first
  * and last items, since there is no list column to carry it.
  *
- * The marker is the renderer's bullet and number, and a checkbox for a task item. It is drawn here
+ * The marker is drawn here rather than by a handler because it is the thing a reader might one day
- * rather than by a handler because it is the thing a reader might one day want styled -- a
+ * want styled -- a different glyph per depth, a colour -- and this is the one place it is drawn.
- * different glyph per depth, a colour -- and this is the one place it is drawn.
  */
 @Composable
 private fun MarkdownListItem(
@@ -231,8 +222,8 @@ private fun Marker(text: String, style: TextStyle) {
 /**
  * The bullet at each depth, cycling past the third: a disc, a ring, a square -- the ladder a
  * browser draws, so a nested list is told from its parent by the glyph as well as by the indent.
- * Checked on the emulator's system fonts, which is what makes them safe to rely on; a glyph the
+ * Checked on the emulator's system fonts; a glyph the platform lacks draws as a box, and that check
- * platform lacks draws as a box, and that check is the price of adding one here.
+ * is the price of adding one here.
  */
 private val BULLETS = listOf("• ", "◦ ", "▪ ")
 

app/androidApp/src/main/kotlin/com/example/aiapp/MarkdownSyntax.kt

@@ -7,23 +7,19 @@ package com.example.aiapp
  * Its own scanner rather than a row of [Rules] because markdown has neither keywords nor strings:
  * what a character means depends on where it sits. A `#` opens a heading at the start of a line and
  * is an ordinary character three words in; a `*` opens emphasis only if something closes it on the
- * same line. The token scanner cannot ask either question, and answering them with its rules is how
+ * same line. The token scanner cannot ask either question.
- * a highlighter comes to grey out the second half of a paragraph.
  *
- * Structure is read a line at a time and each line's prose is then read left to right, so every
+ * Structure is read a line at a time and each line's prose left to right, so every decision is made
- * decision is made inside one line -- except the two things that are not one line. A fenced block
+ * inside one line -- except the two that are not. A fenced block is state carried forward, so an
- * is state carried forward, so an unclosed fence colours the rest of the text, which is also what
+ * unclosed fence colours the rest of the text, which is what it looks like while somebody is
- * it looks like while somebody is still writing it. A table is found by its delimiter row
+ * writing it. A table is found by its delimiter row (`|---|---|`), the only line of one that cannot
- * (`|---|---|`), which is the only line of one that cannot be anything else, and its header is the
+ * be anything else, and its header is the line before that -- the one place here that looks ahead.
- * line before that -- the one place here that looks ahead.
  *
  * What is deliberately *not* recognised: an indented code block. Four spaces after a blank line is
- * one, and four spaces after a bullet is a list item's second paragraph, and the two are told apart
+ * one, four spaces after a bullet is a list item's second paragraph, and the two are told apart by
- * by what came before rather than by the line itself. Colouring the wrong one of those as code is a
+ * what came before. Colouring the wrong one as code is a mistake the reader cannot see.
- * mistake the reader cannot see, so both are left plain, which is the safe answer.
  *
- * Like [scan], the spans come out ordered, non-overlapping and inside the text by construction:
+ * Like [scan], the spans come out ordered, non-overlapping and inside the text by construction.
- * every one is emitted by a pass that only moves forward, and nothing here throws.
  */
 fun scanMarkdown(code: String): List<Span> = MarkdownScanner(code).run()
 
@@ -36,7 +32,7 @@ private const val RULE_MARKERS = "-*_="
 /** The characters that can open emphasis, strong emphasis or a strikethrough. */
 private const val EMPHASIS = "*_~"
 
-/** Characters that end a bare URL wherever they appear in it, and ones only trimmed off the end. */
+/** Characters that end a bare URL wherever they appear, and ones only trimmed off the end. */
 private const val URL_STOPS = "<>\"'`|"
 private const val URL_TRAILING = ".,:;!?"
 
@@ -53,8 +49,8 @@ private class MarkdownScanner(private val code: String) {
             val end = lineEnd(at)
             val open = fence
             if (open != null) {
-                // The content and the closing line alike: a fence is one block of code, and its
+                // The content and the closing line alike: a fence is one block of code, and its own
-                // own delimiters belong to it the way a string's quotes belong to the string.
+                // delimiters belong to it the way a string's quotes belong to the string.
                 emit(at, end, Kind.STRING)
                 if (closesFence(at, end, open)) fence = null
             } else {
@@ -77,11 +73,10 @@ private class MarkdownScanner(private val code: String) {
     /**
      * One line that is not inside a fence, and whether the table it may be part of is still open.
      *
-     * A table is recognised by its delimiter row (`|---|---|`), which is the only line of one that
+     * A table is recognised by its delimiter row, the only line of one that cannot be anything
-     * cannot be anything else. That row comes *after* the header it belongs to, so the header is
+     * else. That row comes *after* the header it belongs to, so the header is found by looking one
-     * found by looking one line ahead -- the single piece of lookahead here, and cheaper than the
+     * line ahead -- the single piece of lookahead here, and cheaper than colouring every `|` in the
-     * alternative of colouring every `|` in the document, which would mark the pipes in a shell
+     * document, which would mark the pipes in a shell command written in a paragraph.
-     * command written in a paragraph.
      */
     private fun row(start: Int, end: Int, table: Boolean): Boolean {
         if (tableDelimiter(start, end)) {
@@ -142,10 +137,9 @@ private class MarkdownScanner(private val code: String) {
     }
 
     /**
-     * Spans, coalesced with the one before when they touch and agree.
+     * Spans, coalesced with the one before when they touch and agree. Worth doing here rather than
-     *
+     * leaving it to the caller: the line scanner emits per marker and per word, so a heading would
-     * Worth doing here rather than leaving it to the caller: the line scanner emits per marker and
+     * otherwise arrive as a dozen abutting spans of one colour.
-     * per word, so a heading would otherwise arrive as a dozen abutting spans of one colour.
      */
     private fun emit(start: Int, end: Int, kind: Kind) {
         if (end <= start) return
@@ -179,17 +173,16 @@ private class MarkdownScanner(private val code: String) {
     private fun opensFence(start: Int, end: Int): String? {
         val run = fenceRun(start, end) ?: return null
         emit(run.first, run.last + 1, Kind.STRING)
-        // The info word is what the fence is a fence *of*, which is metadata about the block
+        // The info word is what the fence is a fence *of*, which is metadata about the block rather
-        // rather than part of it -- the same reading as a Rust attribute above a struct.
+        // than part of it.
         emit(indented(run.last + 1, end), end, Kind.METADATA)
         return code.substring(run.first, run.last + 1)
     }
 
     /**
-     * Whether this line closes a fence opened by [open].
+     * Whether this line closes a fence opened by [open]: the same character, at least as many of
-     *
+     * them, and nothing else on the line -- so a longer run closes a shorter one and a line of
-     * The same character, at least as many of them, and nothing else on the line -- so a longer run
+     * backticks with a word after it does not close anything.
-     * closes a shorter one and a line of backticks with a word after it does not close anything.
      */
     private fun closesFence(start: Int, end: Int, open: String): Boolean {
         val run = fenceRun(start, end) ?: return false
@@ -227,10 +220,9 @@ private class MarkdownScanner(private val code: String) {
      * A line made of one repeated rule character and nothing else.
      *
      * `---`, `***` and `___` are thematic breaks; `===` and `---` are also the underline of a
-     * setext heading. The two are the same line to look at and mean the same thing to a reader -- a
+     * setext heading. The two are the same line to look at and mean the same thing to a reader, so
-     * rule drawn across the page -- so they get one appearance rather than a lookback to tell them
+     * they get one appearance rather than a lookback. One `=` is enough because a setext underline
-     * apart. One `=` is enough because a setext underline may be a single character; a break needs
+     * may be a single character; a break needs three, which keeps a `- ` bullet out of here.
-     * three, which is what keeps a `- ` bullet out of here.
      */
     private fun thematicBreak(start: Int, end: Int): Boolean {
         val marker = code[start]
@@ -292,10 +284,9 @@ private class MarkdownScanner(private val code: String) {
     }
 
     /**
-     * `` `code` ``, closed by a run of exactly as many backticks as opened it.
+     * `` `code` ``, closed by a run of exactly as many backticks as opened it. That count is what
-     *
+     * lets a span hold a backtick of its own, and why the search skips over a shorter or longer run
-     * That count is what lets a span hold a backtick of its own (``` ``a ` b`` ```), and it is why
+     * rather than stopping at the first backtick.
-     * the search skips over a shorter or longer run rather than stopping at the first backtick.
      */
     private fun codeSpan(start: Int, end: Int): Int {
         var open = start
@@ -323,9 +314,8 @@ private class MarkdownScanner(private val code: String) {
      * `[text](destination)`, and the same with a leading `!` for an image.
      *
      * The text is drawn as prose -- it is what the reader reads -- so only the brackets around it
-     * are marked, and the destination is metadata: the place the link goes rather than anything
+     * are marked, and the destination is metadata. A `[text]` with no destination after it is left
-     * said to the reader. A `[text]` with no destination after it is left plain, because that is
+     * plain, because that is what a reference link and a bracketed aside look like.
-     * what a reference link and a bracketed aside look like, and neither is worth guessing at.
      */
     private fun link(start: Int, bracket: Int, end: Int): Int {
         var depth = 0
@@ -357,8 +347,7 @@ private class MarkdownScanner(private val code: String) {
      * `<https://example.com>` and `<name@example.com>`, drawn as the destination they are.
      *
      * The angle brackets have to hold no whitespace and something that makes an address of it -- a
-     * scheme's colon or an at sign -- which is what keeps an HTML tag out: `<div>` has neither, and
+     * scheme's colon or an at sign -- which is what keeps an HTML tag out.
-     * `<img src="http://x">` has the colon but also a space.
      */
     private fun autolink(start: Int, end: Int): Int {
         var at = start + 1
@@ -380,13 +369,12 @@ private class MarkdownScanner(private val code: String) {
     /**
      * A bare `scheme://…` written in prose, or null if one does not start here.
      *
-     * A scheme and `://` rather than a list of them, so `ftp`, `file` and `ssh` need no entry, and
+     * A scheme and `://` rather than a list of them, so `ftp`, `file` and `ssh` need no entry.
-     * the pair of colons is what makes the match unambiguous enough to draw without a closer.
      *
      * Where it ends is the part worth stating: the sentence's punctuation is not the address, so a
      * trailing `.` or `,` is given back, and so is a closing bracket unless one opened inside the
-     * URL -- otherwise a link in parentheses loses its `)` to the address. A pipe stops it too,
+     * URL -- otherwise a link in parentheses loses its `)`. A pipe stops it too, because a URL in a
-     * because a URL in a table cell must not swallow the cell's edge.
+     * table cell must not swallow the cell's edge.
      */
     private fun url(start: Int, end: Int): Int? {
         if (start > 0 && isWord(code[start - 1])) return null
@@ -415,14 +403,13 @@ private class MarkdownScanner(private val code: String) {
     }
 
     /**
-     * `*emph*`, `**strong**`, `_emph_` and `~~struck~~`, drawn markers and all.
+     * `*emph*`, `**strong**`, `_emph_` and `~~struck~~`, drawn markers and all -- which is how the
+     * token scanner draws a string: the quotes are part of the thing.
      *
-     * Markers and all because that is how the token scanner draws a string: the quotes are part of
+     * The two guards keep this off code that happens to be in a paragraph: the opener must be
-     * the thing. The two guards are what keep this off code that happens to be in a paragraph --
+     * followed by something to emphasise and the closer preceded by something emphasised, so `a * b
-     * the opener must be followed by something to emphasise and the closer preceded by something
+     * * c` opens nothing and neither does the `*p = *q` of a C fragment. Underscores may not start
-     * emphasised, so `a * b * c` opens nothing and neither does the `*p = *q` of a C fragment.
+     *   or end inside a word, or every `snake_case_name` would be half emphasised.
-     * Underscores additionally may not start or end inside a word, or every `snake_case_name` in a
-     * document would be half emphasised.
      */
     private fun emphasis(start: Int, end: Int): Int {
         val marker = code[start]

app/androidApp/src/main/kotlin/com/example/aiapp/MemoryNote.kt

@@ -25,12 +25,11 @@ import androidx.compose.ui.unit.dp
  * Claude Code marks a sentence that came from its stored memory by wrapping it in `<cc-memory
  * filenames="...">`. Markdown has nothing to say about that, so it arrived on screen as literal
  * angle brackets in the middle of a sentence -- which reads as the model having emitted broken
- * HTML. It is really the opposite: a claim about where something came from, which is worth showing,
+ * HTML. It is really the opposite: a claim about where something came from, and "I was told this
- * because "I was told this before" and "I worked this out just now" are different things and the
+ * before" and "I worked this out just now" are different things the reader cannot otherwise tell
- * reader cannot otherwise tell them apart.
+ * apart.
  *
- * A tag that has not finished arriving is left alone. Streaming means the closing tag may be
+ * A tag that has not finished arriving is left alone: a half-written marker is not a marker yet.
- * seconds away, and a half-written marker is not a marker yet.
  */
 @Composable
 fun AssistantMessage(
@@ -66,12 +65,10 @@ fun AssistantMessage(
  * A reply carrying no notes is drawn from the message as it arrived rather than from the trimmed
  * prose part made while looking for them -- inspecting a message must not change it. That belongs
  * here rather than at the places that need the answer, because [warm] has to name the same strings
- * the rows draw: a string warmed under a key no row ever looks up is a miss that nothing reports,
+ * the rows draw: a string warmed under a key no row ever looks up is a miss nothing reports.
- * and the row pays the parse in the frame it appears, which is the cost being removed.
  *
  * Public because [transcriptUnits] flattens settled replies into the same parts; go through
- * [ParsedReplies.partsOf] on any path that runs per fold or per page, so the scan happens once per
+ * [ParsedReplies.partsOf] on any path that runs per fold or per page.
- * message.
  */
 fun messageParts(text: String): List<MessagePart> {
     val parts = splitMemoryNotes(text)
@@ -83,16 +80,14 @@ fun messageParts(text: String): List<MessagePart> {
  *
  * Closed by default, like a tool call and a peer message and for the same reason: it is not part of
  * what was said to the reader, it is a note about where a claim came from. Left open it breaks the
- * reply in half around a card, which reads as the answer having stopped and restarted -- and these
+ * reply in half around a card, and these arrive several to a message.
- * arrive several to a message.
  *
  * What stays visible is which file it came from, because that is the whole of what the note claims
- * and it is the part a reader scanning for "why does it think that" is looking for.
+ * and the part a reader scanning for "why does it think that" is looking for.
  *
  * Open-ness is the screen's, keyed by the note's own text: a note opened and scrolled past has to
  * still be open on the way back, and a card that remembered for itself would forget the moment the
- * list stopped composing it. The text is a good enough name -- it does not change once the closing
+ * list stopped composing it.
- * tag has arrived, so a note stays open across the moment its reply settles.
  */
 @Composable
 fun MemoryNote(
@@ -148,10 +143,8 @@ private val MEMORY_NOTE =
     Regex("""<cc-memory\s+filenames="([^"]*)"\s*>(.*?)</cc-memory>""", RegexOption.DOT_MATCHES_ALL)
 
 /**
- * Splits [text] into prose and memory notes, in order.
+ * Splits [text] into prose and memory notes, in order. Always returns at least one part, so a
- *
+ * message with no notes is one piece of prose and costs nothing extra to draw.
- * Always returns at least one part, so a message with no notes in it is one piece of prose and
- * costs nothing extra to draw.
  */
 fun splitMemoryNotes(text: String): List<MessagePart> {
     val parts = mutableListOf<MessagePart>()

app/androidApp/src/main/kotlin/com/example/aiapp/ModelName.kt

@@ -5,26 +5,23 @@ package com.example.aiapp
  *
  * One constant rather than a literal in each place, because the two have to agree: a picker whose
  * options cannot say every state its button can display is one you can leave and not get back to.
- * It is also the Claude CLI's own word for "whatever is configured", so choosing it is a request
+ * It is also the Claude CLI's own word for "whatever is configured".
- * the session can act on rather than a name this app made up.
  */
 const val DEFAULT_MODEL = "default"
 
 /**
  * A model's name as a person reads it.
  *
- * Providers answer with their own full identifier -- Claude Code resolves `haiku` to
+ * Providers answer with their own full identifier -- Claude Code resolves `haiku` to `claude-
- * `claude-haiku-4-5-20251001` and reports that, which is the honest answer to "what is this session
+ * haiku-4-5-20251001` and reports that, which is the honest answer to "what is this session using"
- * using" and far too long for a button in a row that also has to hold Stop and Send.
+ * and far too long for a button in a row that also holds Stop and Send.
  *
  * So the two ends that identify nothing are dropped and nothing else is: the vendor prefix, which
  * is the same on every model this app can show, and the release date, which distinguishes builds of
- * one model rather than one model from another. What is left is the part somebody chose --
+ * one model rather than one model from another. Anything that does not look like that is returned
- * `haiku-4-5` -- and anything that does not look like that is returned untouched, since a name this
+ * untouched.
- * does not recognise is a name it has no business editing.
  *
- * A display decision, not a correction: the full name is what the session reports and what a reader
+ * A display decision, not a correction: the full name is what the session reports.
- * is shown when there is room for it.
  */
 fun modelLabel(model: String?): String {
     val name = model?.takeIf { it.isNotBlank() } ?: return DEFAULT_MODEL

app/androidApp/src/main/kotlin/com/example/aiapp/ModelsScreen.kt

@@ -57,12 +57,9 @@ fun ModelsScreen(settings: ServerSettings, reloadToken: Int) {
             }
     }
 
-    // Polled rather than pushed: a download belongs to the machine, not to
+    // Polled rather than pushed: a download belongs to the machine, not to any session, so it has
-    // any session, so it has no event stream of its own. Slow enough not
+    // no event stream of its own. Keyed on the token as well, so the header's Refresh restarts the
-    // to matter, frequent enough that a bar moves.
+    // loop with a read now rather than leaving the reader watching for a second and a half.
-    // Keyed on the token as well, so the header's Refresh restarts the loop with a read now
-    // rather than leaving the reader watching for up to a second and a half to see whether
-    // anything happened.
     LaunchedEffect(reloadToken) {
         while (true) {
             reload()
@@ -186,11 +183,9 @@ fun ModelsScreen(settings: ServerSettings, reloadToken: Int) {
                                     }
                                 }
                             }
-                            // Inside the expanded repository's own item
+                            // Inside the expanded repository's own item rather than as a section
-                            // rather than as a section after the list:
+                            // after the list: drawn after every card, a repository's files read as
-                            // drawn after every card, a repository's files
+                            // belonging to whichever card happened to be last.
-                            // read as belonging to whichever card happened
-                            // to be last.
                             if (open) {
                                 when (val files = repoFiles) {
                                     null -> {}
@@ -257,15 +252,15 @@ private fun DownloadCard(download: Download, onCancel: () -> Unit) {
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )
             Spacer(Modifier.height(8.dp))
-            // A determinate bar only when the size is known. The server
+            // A determinate bar only when the size is known. The server sends no total when it was
-            // sends no total when it was never told one, and a bar drawn
+            // never told one, and a bar drawn from a guess is worse than one that admits it is
-            // from a guess is worse than one that admits it is counting.
+            // counting.
             if (download.total != null && download.total > 0) {
                 LinearProgressIndicator(
                     progress = { download.done.toFloat() / download.total.toFloat() },
                     // Blue at every value, unlike a quota bar: a download nearing its end is
-                    // nearing success, and colouring it like a limit being approached would say
+                    // nearing success, and colouring it like a limit being approached would say the
-                    // the opposite of what is happening.
+                    // opposite.
                     color = progressColor,
                     modifier = Modifier.fillMaxWidth(),
                 )
@@ -327,8 +322,8 @@ private fun RepoRow(repo: RemoteRepo, expanded: Boolean, onToggle: () -> Unit) {
                     repo.id,
                     style = MaterialTheme.typography.titleSmall,
                     maxLines = 1,
-                    // The owner is the part that repeats; the model name at
+                    // The owner is the part that repeats; the model name at the end is what tells
-                    // the end is what tells two entries apart.
+                    // two entries apart.
                     overflow = TextOverflow.StartEllipsis,
                 )
                 Text(
@@ -356,11 +351,9 @@ private fun RepoFileRow(file: RemoteFile, downloading: Boolean, onDownload: () -
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )
         }
-        // Disabled rather than absent, so the row reads the same whether
+        // Disabled rather than absent, so the row reads the same whether this one is absent,
-        // this one is absent, already here, or on its way. Offering
+        // already here, or on its way. Offering "Download" for a file that is downloading would be
-        // "Download" for a file that is downloading would be a button that
+        // a button that does nothing anyone can see.
-        // does nothing anyone can see -- the server joins the running
-        // download rather than starting a second.
         TextButton(enabled = !file.have && !downloading, onClick = onDownload) {
             Text(
                 when {

app/androidApp/src/main/kotlin/com/example/aiapp/NerdIcons.kt

@@ -26,26 +26,21 @@ import androidx.compose.ui.unit.sp
  * set and kept in step by hand.
  *
  * This replaced a hand-drawn canvas gear, whose doc comment argued against icon fonts on the
- * grounds that a system font may not have the glyph and whoever gets the empty box instead is never
+ * grounds that a system font may not have the glyph. That objection is about *relying* on a system
- * the person who wrote it. That objection is about *relying* on a system font, and it is exactly
+ * font, and it is exactly right: the answer is not to avoid glyphs but to ship them. The font here
- * right: the answer is not to avoid glyphs but to ship them. The font here is
+ * is `app/build-icon-font.sh`'s output -- seventeen glyphs, 2.8 KB, subset out of the 3 MB symbols
- * `app/build-icon-font.sh`'s output -- seventeen glyphs, 2.8 KB, subset out of the 3 MB symbols
+ * font and committed. Adding one means adding its codepoint in *both* places; a codepoint here that
- * font and committed -- so the codepoints below are resolved by an asset in the APK and cannot come
+ * the script did not subset is a glyph that silently isn't there.
- * back as tofu. Adding one means adding its codepoint in *both* places; a codepoint here that the
- * script did not subset is a glyph that silently isn't there.
  *
  * The subset is the font's **Mono** face, where every glyph is exactly one em wide and one em tall.
- * That is what makes two icons the same size without either of them being given a size: the
+ * That is what makes two icons the same size without either being given a size: the proportional
- * proportional face's advances run from 0.46 em to 0.92 em, so a Send button and a Stop button side
+ * face's advances run from 0.46 em to 0.92 em, so a Send button and a Stop button side by side came
- * by side came out visibly different widths, and matching them at the call site would have meant
+ * out visibly different widths. [GLYPH_SIZE] carries the cost.
- * one hardcoded measurement per pair. [GLYPH_SIZE] carries the cost.
  *
  * The same arrangement as dev-updater, down to the cog and the refresh arrow being the same two
- * Material Design codepoints. Those two must not drift: an icon that means "settings" in one app
+ * Material Design codepoints. Those two must not drift. The script is copied rather than shared
- * and something else in the other is the failure this is worth preventing. The script is copied
+ * because most of what looks like duplication is the `GLYPHS` list, which has to differ -- the
- * rather than shared because most of what looks like duplication is the `GLYPHS` list, which has to
+ * point of subsetting is to ship only the codepoints one app draws.
- * differ -- the point of subsetting is to ship only the codepoints one app draws. All Material
- * Design bar one, so they read as one family; the exception is noted where it is declared.
  */
 val NerdIcons = FontFamily(Font(R.font.nerd_icons))
 
@@ -74,8 +69,7 @@ val STOP_GLYPH = glyph(0xF04DB)
  *
  * The pair with [STOP_GLYPH] and [PLAY_GLYPH] is the point: one button in the composer says what
  * pressing it now would do to the process, and the three marks are the three answers. An interrupt
- * ends a turn and nothing else -- the CLI is still there and still holds the conversation -- which
+ * ends a turn and nothing else, which is a pause, not a stop.
- * is a pause, not a stop, and drawing it as a square said otherwise.
  */
 val PAUSE_GLYPH = glyph(0xF03E4)
 
@@ -86,8 +80,8 @@ val PLAY_GLYPH = glyph(0xF040A)
  * `md-send_clock` -- the same paper plane with a clock on it: this message will wait its turn.
  *
  * The pair with [SEND_GLYPH] is the point. Sending during a turn queues the message rather than
- * starting one, and the two buttons have to be told apart at a glance -- one glyph doing both jobs
+ * starting one, and one glyph doing both jobs would promise something immediate and do something
- * while looking identical would promise something immediate and do something that waits.
+ * that waits.
  */
 val QUEUE_GLYPH = glyph(0xF1163)
 
@@ -104,8 +98,7 @@ val BELL_GLYPH = glyph(0xF009A)
  * `fa-line_chart` -- how much of the account's rate limits is gone.
  *
  * Font Awesome's rather than Material's, which is the one break in the family above: it was asked
- * for by name, and Material's chart glyphs are a bare line where this one has its axes, which is
+ * for by name, and Material's chart glyphs are a bare line where this one has its axes.
- * what makes it read as a measurement rather than as a trend.
  */
 val USAGE_GLYPH = glyph(0xF201)
 
@@ -121,9 +114,8 @@ val SPEED_GLYPH = glyph(0xF04C5)
  * `md-folder` -- the files on the machine this session runs on.
  *
  * The same codepoint dev-updater uses, and it must not drift from it, for the reason the cog and
- * the refresh arrow must not: a folder that meant something else in one of the two apps is exactly
+ * the refresh arrow must not. Doubles as the mark on a directory row inside the explorer, which is
- * the confusion sharing them prevents. Doubles as the mark on a directory row inside the explorer,
+ * what makes the button say where it leads.
- * which is what makes the button say where it leads.
  */
 val FOLDER_GLYPH = glyph(0xF024B)
 
@@ -148,10 +140,9 @@ val SAVE_GLYPH = glyph(0xF0193)
  * The size an icon draws at beside a line of text.
  *
  * 17 rather than the 20 it was while the font was the proportional face. A glyph there filled at
- * most 0.83 em of its point size and most filled a good deal less, so the number was standing in
+ * most 0.83 em of its point size, so the number was standing in for the headroom above the tallest
- * for the headroom above the tallest one; in the Mono face every glyph fills its em exactly, and
+ * one; in the Mono face every glyph fills its em exactly, and keeping 20 would have stepped every
- * keeping 20 would have made every icon in the app step up by a fifth for no reason anybody asked
+ * icon in the app up by a fifth.
- * for. This is what the largest of them already drew at.
  */
 private val GLYPH_SIZE = 17.sp
 
@@ -165,16 +156,14 @@ private val GLYPH_EXTENT = GLYPH_SIZE.value.dp
  *
  * The ring is the whole spacing rule. Every gap around a header icon comes out of it -- one ring to
  * the screen edge, two where a button meets its neighbour -- so nothing outside has to add a gap of
- * its own, and a mark cannot end up further from the button beside it than from the edge of the
+ * its own. That is what it was: the box was the size of the mark (28dp) and the separation was
- * screen. That is what it was: the box was the size of the mark (28dp) and the separation was
  * bolted on beside it, which left the two header icons 31dp apart and the outer one 14dp from the
- * edge, so a pair that acts on one screen read as two unrelated marks with one falling off it.
+ * edge.
  *
  * 48dp is the platform's minimum touch target, so the square is also the whole of what a finger has
- * to find. It is what the pressed-state ripple draws, too: at 28dp that circle was inscribed in the
+ * to find, and what the pressed-state ripple draws: at 28dp that circle was inscribed in the mark's
- * mark's own corners, and beside a title it arrived at the first letter. And it is taller than any
+ * own corners and beside a title it arrived at the first letter. And it is taller than any header's
- * header's text, which is what lets the button fill a header row rather than sit in the middle of
+ * text, which is what lets the button fill a header row rather than sit in the middle of one.
- * one -- the rows add no vertical padding of their own for the same reason they add no gap.
  */
 private val GLYPH_BUTTON_SIZE = 48.dp
 
@@ -182,11 +171,9 @@ private val GLYPH_BUTTON_SIZE = 48.dp
  * The ring itself, for putting something that is *not* a glyph button next to one -- a title beside
  * a back arrow.
  *
- * Two glyph buttons need nothing between them: each brings its own ring and the two add up, which
+ * Two glyph buttons need nothing between them: each brings its own ring and the two add up. Text
- * is why a row of them sets no spacing. Text brings none, so the second ring has to be asked for.
+ * brings none, so the second ring has to be asked for -- without it the pressed-state circle
- * Without it the pressed-state circle, which fills the whole square, arrives at the first letter of
+ * arrives at the first letter of the title.
- * the title -- and the gap a reader sees between the mark and that title is then half the one
- * between the two marks at the other end of the same row.
  */
 val GLYPH_BUTTON_MARGIN = (GLYPH_BUTTON_SIZE - GLYPH_EXTENT) / 2
 
@@ -195,8 +182,7 @@ val GLYPH_BUTTON_MARGIN = (GLYPH_BUTTON_SIZE - GLYPH_EXTENT) / 2
  *
  * Its own composable so that every icon button in the app is one size and one colour without each
  * caller saying so, and so the [label] none of them displays is still there for a screen reader --
- * which is all assistive technology has to go on, and also the answer to "what was that button for"
+ * which is also the answer to "what was that button for" six months from now.
- * six months from now.
  *
  * [enabled] is passed through rather than left to callers hiding the button: a control that comes
  * and goes makes its own absence the signal, and absence cannot say whether there was nothing to do
@@ -220,9 +206,8 @@ fun GlyphButton(
  * The same square, around a mark that is not a glyph.
  *
  * A [Chevron] is drawn rather than set in a font, and a pair of them used as buttons has to be the
- * size, spacing and touch target every other icon button on this app's headers already is -- so
+ * size, spacing and touch target every other icon button already is. The caller still owes it a
- * this is [GlyphButton] with the mark left to the caller rather than a second set of measurements
+ * [label]: nothing here draws a word.
- * beside it. The caller still owes it a [label]: nothing here draws a word.
  */
 @Composable
 fun MarkButton(
@@ -245,9 +230,7 @@ fun MarkButton(
  * The square a glyph button occupies, with a spinner in it instead of a mark.
  *
  * For a button whose work is under way. It takes the button's whole box rather than the mark's, so
- * swapping one for the other leaves everything in the row exactly where it was -- a control that
+ * swapping one for the other leaves everything in the row exactly where it was.
- * changed the width of its header while it worked would move its neighbours at the moment somebody
- * was pressing them.
  */
 @Composable
 fun GlyphSpinner(label: String, modifier: Modifier = Modifier) {
@@ -273,10 +256,9 @@ fun Glyph(
     size: TextUnit = GLYPH_SIZE,
 ) {
     // Line height of the point size, which for this font is the square the glyph draws in: its
-    // ascent and descent add up to exactly one em, and every glyph in the Mono face fills that em.
+    // ascent and descent add up to exactly one em. Left to the inherited body style the line box
-    // Left to the inherited body style the line box was 24sp tall around a 17sp-wide mark, so a
+    // was 24sp tall around a 17sp-wide mark, so a glyph took a seventh more vertical space than
-    // glyph took a seventh more vertical space than horizontal wherever one is drawn without a box
+    // horizontal.
-    // around it -- and where there is a box, that leading is what its padding is measured through.
     Text(
         glyph,
         fontFamily = NerdIcons,

app/androidApp/src/main/kotlin/com/example/aiapp/Notifications.kt

@@ -34,12 +34,11 @@ import org.json.JSONObject
  * gets a push from Google's servers, which would mean this backend talking to Google about
  * somebody's coding sessions, and the whole point of the tunnel is that it does not.
  *
- * The cost Android charges for it is a notification of its own that cannot be dismissed. That is
+ * The cost Android charges is a notification of its own that cannot be dismissed. That is made as
- * made as quiet as the platform allows: [ONGOING_CHANNEL] is `IMPORTANCE_MIN`, so it makes no
+ * quiet as the platform allows: [ONGOING_CHANNEL] is `IMPORTANCE_MIN`, so it makes no sound, shows
- * sound, shows no status-bar icon, and sits at the bottom of the shade -- the same arrangement
+ * no status-bar icon, and sits at the bottom of the shade. It is not hidden outright, because it
- * Syncthing's "hide the persistent notification" option produces. It is not hidden outright,
+ * cannot be and because it should not be: it is the honest indicator that something is holding a
- * because it cannot be and because it should not be: it is the honest indicator that something is
+ * connection open.
- * holding a connection open.
  */
 class NotificationService : Service() {
     @Volatile private var stream: HttpURLConnection? = null
@@ -50,18 +49,18 @@ class NotificationService : Service() {
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
         val settings = loadServerSettings(this)
         if (settings == null) {
-            // Nothing to connect to. Stopping rather than idling: a service
+            // Nothing to connect to. Stopping rather than idling: a service holding no connection
-            // holding no connection still costs the ongoing notification,
+            // still costs the ongoing notification, which would be announcing work that is not
-            // which would then be announcing work that is not happening.
+            // happening.
             stopSelf()
             return START_NOT_STICKY
         }
-        // Through ServiceCompat so the type is stated once and ignored on
+        // Through ServiceCompat so the type is stated once and ignored on the versions that predate
-        // the versions that predate types, rather than branching here.
+        // types, rather than branching here.
         ServiceCompat.startForeground(this, ONGOING_ID, ongoingNotification(), foregroundType())
         thread(isDaemon = true, name = "ai-app-notifications") { follow(settings) }
-        // Restarted if Android kills it, which is the whole point: the
+        // Restarted if Android kills it, which is the whole point: the window this covers is
-        // window this covers is exactly the one where nobody is watching.
+        // exactly the one where nobody is watching.
         return START_STICKY
     }
 
@@ -73,11 +72,10 @@ class NotificationService : Service() {
     /**
      * Follows the backend's notification stream, reconnecting until stopped.
      *
-     * A dropped connection is the ordinary case here rather than an error -- a phone changes
+     * A dropped connection is the ordinary case here rather than an error, so it retries quietly
-     * networks, the tunnel comes and goes, the backend restarts -- so it retries quietly and
+     * and forever. Nothing is shown when it cannot connect: a notification saying "I could not tell
-     * forever. Nothing is shown when it cannot connect: a notification saying "I could not tell you
+     * you whether anything happened" is noise about a condition nobody can act on, and the session
-     * whether anything happened" on a phone in somebody's pocket is noise about a condition they
+     * list already says what is waiting when they next look.
-     * cannot act on, and the session list already says what is waiting when they next look.
      */
     private fun follow(settings: ServerSettings) {
         while (!stopping) {
@@ -102,8 +100,8 @@ class NotificationService : Service() {
         try {
             connection.applyPinnedTls()
             connection.connectTimeout = CONNECT_TIMEOUT_MS
-            // No read timeout, for the reason EventStream gives: between
+            // No read timeout, for the reason EventStream gives: between notifications there is
-            // notifications there is nothing to read, possibly for hours.
+            // nothing to read, possibly for hours.
             connection.readTimeout = 0
             connection.setRequestProperty("Authorization", "Bearer ${settings.token}")
             connection.setRequestProperty("Accept", "text/event-stream")
@@ -134,28 +132,23 @@ class NotificationService : Service() {
      *
      * Keyed by session id rather than accumulating: two sessions wanting attention are two things
      * to know about, but one session that finished and then asked a question is one thing -- the
-     * question. A stack of stale rows for the same conversation is how a notification drawer
+     * question. A stack of stale rows is how a drawer becomes something to clear rather than read.
-     * becomes something to clear rather than read.
      */
     private fun show(notification: SessionNotification) {
         // Nothing to tell somebody about the session they are reading. The transcript in front of
-        // them is already saying it, and a sound over the top of it would be this app announcing
+        // them is already saying it.
-        // what the screen is showing.
         if (isOnScreen(notification.sessionId)) return
-        // The app is up: it says this itself, as a banner over whatever screen they are on. See
+        // The app is up: it says this itself, as a banner over whatever screen they are on. Never
-        // [forTheScreen]. Never both -- one thing happened, and a drawer filling up behind an
+        // both -- one thing happened, and a drawer filling up behind an app that already showed you
-        // app that already showed you each one is a drawer nobody reads.
+        // each one is a drawer nobody reads.
         if (handOver(notification)) return
         val manager = NotificationManagerCompat.from(this)
         // Two different noes, and both are answers rather than faults: the runtime permission
-        // refused, and notifications switched off for the app in Android's own settings. Neither
+        // refused, and notifications switched off for the app in Android's own settings.
-        // is reported anywhere -- the person said no, and saying it back to them through the
-        // channel they closed is not available anyway.
         //
         // The permission only exists from Android 13. Asking an older version about it gets
-        // "denied" for a name it does not know, which read as the person having said no -- so
+        // "denied" for a name it does not know, which read as the person having said no -- so every
-        // every notification on Android 12 and below was silently dropped. Before 13 the
+        // notification on Android 12 and below was silently dropped.
-        // switch in Android's own settings, checked below, is the whole of the answer.
         val allowed =
             Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU ||
                 ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS) ==
@@ -187,9 +180,8 @@ class NotificationService : Service() {
      * The type Android 14+ requires a foreground service to declare, and nothing before it.
      *
      * Named behind a version check rather than passed as a constant: the value is inlined at
-     * compile time and would be handed to platforms that have no concept of it, which is exactly
+     * compile time and would be handed to platforms that have no concept of it, which is what
-     * the case lint's InlinedApi exists to catch. Zero is what ServiceCompat wants where types do
+     * lint's InlinedApi exists to catch.
-     * not apply.
      */
     private fun foregroundType(): Int =
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
@@ -226,11 +218,10 @@ class NotificationService : Service() {
         /**
          * Two channels, because they are two different things to be told.
          *
-         * The alerts are what somebody turned this on for, so they get the default importance and
+         * The alerts are what somebody turned this on for, so they get the default importance. The
-         * whatever sound and heads-up display the person has chosen for the app. The ongoing one is
+         * ongoing one is the platform's tax for staying connected, so it takes the lowest
-         * the platform's tax for staying connected, so it takes the lowest importance that exists.
+         * importance that exists. Both are created before the service starts, since posting to a
-         * Both are created before the service starts, since posting to a channel that does not
+         * channel that does not exist is silently dropped.
-         * exist is silently dropped.
          */
         private fun createChannels(context: Context) {
             val manager = NotificationManagerCompat.from(context)
@@ -256,12 +247,10 @@ class NotificationService : Service() {
          * The session somebody is looking at, or null when no screen is showing one.
          *
          * Process-wide state, which the rest of this app does without: Android constructs the
-         * service and the composition draws the screen, so the two have no common owner a value
+         * service and the composition draws the screen, so the two have no common owner. Clearing
-         * could be passed through. [showing] and [stoppedShowing] are the pair, both called from
+         * names the session rather than setting null outright, because moving from one session to
-         * the one composable that shows a session. Clearing names the session rather than setting
+         * another composes the new screen before the old one's coroutine is cancelled -- an
-         * null outright, because moving from one session to another composes the new screen before
+         * unconditional clear would throw away the new screen's claim.
-         * the old one's coroutine is cancelled -- an unconditional clear would then throw away the
-         * new screen's claim and start notifying about what is on it.
          */
         @Volatile private var onScreen: String? = null
 
@@ -271,10 +260,9 @@ class NotificationService : Service() {
          * The way a notification reaches the app instead of Android's drawer.
          *
          * Whether there is an app to reach is the subscriber count rather than a flag of its own:
-         * [SessionAlerts] collects this exactly while it is on screen, so there is nothing that
+         * [SessionAlerts] collects this exactly while it is on screen. `tryEmit` neither suspends
-         * could be left saying the app is up after it has gone. `tryEmit` neither suspends nor
+         * nor blocks the thread reading the stream, and the buffer is there so a handful of
-         * blocks the thread reading the stream, and the buffer is there so a handful of sessions
+         * sessions finishing together all land rather than the last one winning.
-         * finishing together all land rather than the last one winning.
          */
         private val toApp = MutableSharedFlow<SessionNotification>(extraBufferCapacity = 8)
 
@@ -287,9 +275,8 @@ class NotificationService : Service() {
         /** Somebody is looking at [sessionId]; nothing is posted about it until they stop. */
         fun showing(context: Context, sessionId: String) {
             onScreen = sessionId
-            // Whatever was posted about it before is about to be read, so it has nothing left
+            // Whatever was posted about it before is about to be read, so it has nothing left to
-            // to say -- and a row in the drawer for the conversation on screen is the same
+            // say.
-            // duplication this whole rule is about.
             NotificationManagerCompat.from(context).cancel(sessionId, ALERT_ID)
         }
 
@@ -311,8 +298,8 @@ class NotificationService : Service() {
  * The intent that opens one session, and the id it carries back out.
  *
  * The two halves are written together so neither can be changed without the other, and the scheme
- * is enrollment's `aiapp://` under a different host so that [MainActivity] has one thing to look at
+ * is enrollment's `aiapp://` under a different host so that [MainActivity] has one thing to look
- * when an intent arrives rather than two.
+ * at.
  *
  * The id rides in the intent's **data** rather than in an extra, which is not a style choice:
  * PendingIntent identity is `Intent.filterEquals`, and that compares the data while ignoring
@@ -345,9 +332,8 @@ data class SessionNotification(
  * What a notification asks of the reader, in the words they see.
  *
  * What they have to do, not what the session did: "awaitingInput" is the wire's word and says
- * nothing to somebody reading a lock screen. One function because the same fact is now shown in two
+ * nothing to somebody reading a lock screen. One function because the same fact is shown in two
- * places -- Android's drawer and the app's own banner -- and two mappings of one word drift. The
+ * places -- Android's drawer and the app's own banner -- and two mappings of one word drift.
- * banner colours the line as well, which is its own decision and stays with the drawing.
  */
 fun attentionLine(kind: String): String =
     when (kind) {

app/androidApp/src/main/kotlin/com/example/aiapp/PeerMessage.kt

@@ -31,13 +31,12 @@ import androidx.compose.ui.unit.dp
  *
  * Drawn as its own kind rather than as the reader's own bubble. They did not say this, and a
  * transcript that puts it in their voice is making a claim about who asked for the work that
- * follows -- which is exactly the question a peer message is usually the answer to.
+ * follows.
  *
  * Opened, the card is drawn in *pieces* -- this heading and one [PeerBlockRow] per markdown block,
- * each its own item of the transcript list. See [TranscriptUnit.PeerHead] for the measurements that
+ * each its own item of the transcript list. See [TranscriptUnit.PeerHead] for what that bought;
- * bought; what matters here is that the pieces have to add up to the card that was there before, so
+ * what matters here is that the pieces have to add up to the card that was there before, so the
- * the fill, the corner radius and the padding all live in [peerSurface] rather than being written
+ * fill, the corner radius and the padding all live in [peerSurface].
- * out at each piece.
  */
 @Composable
 fun PeerHeadRow(
@@ -91,9 +90,9 @@ fun PeerBlockRow(unit: TranscriptUnit.PeerBlock, replies: ParsedReplies, onToggl
         // The words shut the card too, and have to do it themselves -- see [LocalMarkdownTap].
         // Without this the card closes everywhere except on the text, which is most of it.
         CompositionLocalProvider(LocalMarkdownTap provides rememberMarkdownTap(onToggle)) {
-            // The gap the card's own column used to provide between its heading and its prose,
+            // The gap the card's own column used to provide between its heading and its prose, and
-            // and between one block and the next -- inside the piece, so the card's fill runs
+            // between one block and the next -- inside the piece, so the card's fill runs through
-            // through it.
+            // it.
             MarkdownPiece(unit.text, unit.piece, replies, Modifier.padding(top = unit.spacing))
         }
     }
@@ -102,16 +101,14 @@ fun PeerBlockRow(unit: TranscriptUnit.PeerBlock, replies: ParsedReplies, onToggl
 /**
  * One piece of a card drawn in slices: the fill, the corners it owns, and the room inside it.
  *
- * A filled Material card is elevation zero ([CardDefaults] takes it from `FilledCardTokens`, which
+ * A filled Material card is elevation zero, so there is no shadow that a seam would show through --
- * is `Level0`), so there is no shadow that a seam would show through -- which is the whole reason a
+ * which is the whole reason a card can be cut up at all. Each piece paints the caller's container
- * card can be cut up at all. Each piece paints the caller's container colour the way a
+ * colour and rounds only the corners at the ends of the message, so the pieces abut into one
- * [androidx.compose .material3.Card] would and rounds only the corners at the ends of the message,
+ * continuous card. Shared by the two rows cut this way -- an opened peer message and a long user
- * so the pieces abut into one continuous card. Shared by the two rows that are cut this way -- an
+ * message -- because two copies of the corner logic is how one of them grows a seam.
- * opened peer message and a long user message -- because two copies of the corner logic is how one
- * of them grows a seam.
  *
- * The padding is the other half of it: 12dp all round was the card's own, so the top piece keeps
+ * The padding is the other half: 12dp all round was the card's own, so the top piece keeps the top
- * the top of it, the bottom piece the bottom, and the middle pieces neither.
+ * of it, the bottom piece the bottom, and the middle pieces neither.
  */
 @Composable
 fun Modifier.cardPiece(

app/androidApp/src/main/kotlin/com/example/aiapp/PendingAttachments.kt

@@ -34,13 +34,10 @@ import androidx.compose.ui.unit.sp
  * What is about to be sent, directly above the box it will be sent from.
  *
  * The count on the "+" button was the whole of what said an image was attached, so the only way to
- * find out *which* image was to send it. A control belongs with the thing it acts on, and what
+ * find out *which* image was to send it. A control belongs with the thing it acts on.
- * these are attached to is the message being typed -- which is why they sit here rather than
- * anywhere else on the screen.
  *
  * Scrolls sideways rather than wrapping or shrinking: the row keeps one thumbnail size whatever is
- * in it, so four attachments look like four of the same thing rather than four smaller ones. A file
+ * in it, so four attachments look like four of the same thing rather than four smaller ones.
- * is a tile of the same height carrying its name, since a name is all there is to show of it.
  */
 @Composable
 fun PendingAttachments(
@@ -67,8 +64,7 @@ fun PendingAttachments(
  *
  * Removal is here because there is nowhere else it could be: an image picked by mistake could
  * otherwise only be dealt with by sending it. The whole thumbnail is the target rather than a
- * corner cross -- a cross small enough to sit on a 64dp square is smaller than a fingertip -- and
+ * corner cross -- a cross small enough to sit on a 64dp square is smaller than a fingertip.
- * the label is what says so, since nothing about the picture does.
  */
 @Composable
 private fun PendingThumbnail(
@@ -84,8 +80,7 @@ private fun PendingThumbnail(
             .clip(shape)
             // An outline as well as a fill. Most of what gets attached here is a screenshot of a
             // dark app, and cropped to a square its middle is often near-black -- against this
-            // background the tile then had no edge at all, and the only thing saying an image was
+            // background the tile then had no edge at all.
-            // attached was the cross drawn on top of nothing.
             .border(1.dp, MaterialTheme.colorScheme.outlineVariant, shape)
             // Behind the picture as well as under a missing one, so the tile is a tile before
             // anything has arrived to fill it.
@@ -105,9 +100,9 @@ private fun PendingThumbnail(
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                     )
                 } else {
-                    // A spinner, as the transcript's images have: one appearance for "a picture
+                    // A spinner, as the transcript's images have: one appearance for "a picture is
-                    // is on its way", learned once. An ellipsis had to be read as a spinner that
+                    // on its way", learned once. An ellipsis had to be read as a spinner not
-                    // was not moving.
+                    // moving.
                     CircularProgressIndicator(Modifier.size(20.dp), strokeWidth = 2.dp)
                 }
             else ->
@@ -118,14 +113,12 @@ private fun PendingThumbnail(
                     modifier = Modifier.size(THUMBNAIL),
                 )
         }
-        // The whole square removes it, and this only says so. A cross small enough to sit in
+        // The whole square removes it, and this only says so. A cross small enough to sit in the
-        // the corner of a 64dp thumbnail is smaller than a fingertip, so making it the target
+        // corner of a 64dp thumbnail is smaller than a fingertip.
-        // would be a control drawn at a size nobody can hit.
         //
         // The disc is sized here and the mark centred inside it, rather than the glyph being
-        // aligned directly: a glyph's box is wider than the cross it draws, so aligning the box
+        // aligned directly: a glyph's box is wider than the cross it draws, so aligning the box to
-        // to the corner hung the visible mark over the edge and put its backing somewhere the
+        // the corner hung the visible mark over the edge.
-        // eye reads as a second, misplaced square.
         Box(
             Modifier.align(Alignment.TopEnd)
                 .padding(2.dp)

app/androidApp/src/main/kotlin/com/example/aiapp/PinnedCert.kt

@@ -3,15 +3,13 @@ package com.example.aiapp
 import com.example.wgapplink.PinnedTls
 import java.net.HttpURLConnection
 
-// PINNED_CA_PEM is generated at build time from the CA on the machine doing
+// PINNED_CA_PEM is generated at build time from the CA on the machine doing the build -- see the
-// the build -- see the generatePinnedCert task in build.gradle.kts. It is
+// generatePinnedCert task in build.gradle.kts. It is deliberately not a checked-in constant: the
-// deliberately not a checked-in constant: the private key that signs against
+// private key that signs against it must never be anywhere this repo is, and an APK should pin
-// it must never be anywhere this repo is, and an APK should pin whatever CA
+// whatever CA the backend it was built for actually serves.
-// the backend it was built for actually serves.
 //
-// The pinning itself lives in wg-app-link, since dev-updater needs exactly
+// The pinning itself lives in wg-app-link, since dev-updater needs exactly the same thing. What
-// the same thing. What stays here is the one product-specific fact -- which
+// stays here is which certificate this app pins.
-// certificate this app pins.
 private val pinned = PinnedTls(PINNED_CA_PEM)
 
 /** Every request this app makes goes through this -- there is no unpinned path. */

app/androidApp/src/main/kotlin/com/example/aiapp/RawBlock.kt

@@ -16,20 +16,17 @@ import androidx.compose.ui.unit.dp
  *
  * A composable rather than a modifier repeated at each site, because the inset is part of it --
  * monospace text drawn hard against the edge of a tinted block reads as a clipping fault, and three
- * copies of "clip, fill, pad" drift apart the first time one of them is adjusted.
+ * copies of "clip, fill, pad" drift apart the first time one is adjusted.
  *
- * The colour is [rawSurface], which is also what a code block inside a reply is given; that is the
+ * The colour is [rawSurface], which is also what a code block inside a reply is given.
- * point of having one name for it. Markdown's blocks are painted by the renderer rather than by
- * this, since it draws its own, but they are the same colour on purpose.
  */
 @Composable
 fun RawBlock(modifier: Modifier = Modifier, content: @Composable ColumnScope.() -> Unit) {
     Column(
         modifier
             .fillMaxWidth()
-            // Smaller than a card's radius, and deliberately: this sits *inside* one, and a
+            // Smaller than a card's radius, and deliberately: this sits *inside* one, and a rounded
-            // rounded rectangle drawn at the same radius as the rounded rectangle behind it reads
+            // rectangle drawn at the same radius as the one behind it reads as a misprint.
-            // as a misprint rather than as nesting.
             .clip(MaterialTheme.shapes.extraSmall)
             .background(rawSurface)
             .padding(horizontal = 8.dp, vertical = 6.dp),

app/androidApp/src/main/kotlin/com/example/aiapp/ResetCountdown.kt

@@ -4,17 +4,16 @@ import java.time.Duration
 import java.time.OffsetDateTime
 
 // How long is left in a usage window. Shared by the session bar and the usage screen: the
-// arithmetic is the same in both and only the sentence around it differs, so everything here
+// arithmetic is the same in both, so everything here returns the span or the state on its own and
-// returns the span or the state on its own and leaves the wording to the caller.
+// leaves the wording to the caller.
 
 /**
  * "1d 4h", "3h 12m", "12m" -- the span alone, with no leading or trailing words.
  *
  * Rounded **up** to the whole minute, rather than truncated as it was. A window with 3h 12m 50s
  * left is nearer four minutes past the twelve than it is to twelve, and truncating also parks the
- * figure on a minute it has already spent -- so the reader watching the number decide whether to
+ * figure on a minute it has already spent. One rule, so the session bar and the usage dialog cannot
- * start something was consistently told less headroom than they had. One rule, so the session bar
+ * round a shared measurement two different ways.
- * and the usage dialog cannot round a shared measurement two different ways.
  */
 fun formatSpan(until: Duration): String {
     val up = if (until.seconds % 60 == 0L && until.nano == 0) until else until.plusMinutes(1)
@@ -31,14 +30,12 @@ fun formatSpan(until: Duration): String {
  * Three answers rather than a nullable duration, because two of them shared `null` and they are not
  * the same thing at all. A window the server sent no reset time for is one that is **not running**:
  * the five-hour window is anchored to the block it started in, so between sessions there is nothing
- * counting down and the API says so by omitting the field -- measured against a live response on
+ * counting down and the API says so by omitting the field. A timestamp that did arrive and could
- * 2026-08-31, where the five-hour window's reset was exactly five hours after the moment work
+ * not be read is the genuinely unknown case.
- * resumed. A timestamp that did arrive and could not be read is the genuinely unknown case, and it
- * is the only one worth those words.
  *
  * Collapsing them put "reset time unknown" on the session bar for a machine behaving perfectly, on
  * the one row somebody reads before starting something big -- and the usage dialog, looking at the
- * same field, quietly drew nothing. Two rules for one missing value; this is the rule.
+ * same field, quietly drew nothing.
  */
 sealed class WindowEnd {
     /** No reset time was sent, so nothing is running in this window. Not a failure to find out. */

app/androidApp/src/main/kotlin/com/example/aiapp/ScrollAnchor.kt

@@ -10,24 +10,21 @@ private const val ANCHORS = "session-scroll"
  *
  * Named by a **sequence number** -- see [TranscriptRow.startSeq] -- rather than by an index or by
  * the row key the list draws with. An index means nothing across a reopen, since the transcript is
- * fetched newest-first and a session that has said anything since has renumbered every position.
+ * fetched newest-first. The row key looks stable and is not: a tool row is named after its run,
- * The row key looks stable and is not: a tool row is named after its run, `joinPages` gives a run
+ * `joinPages` gives a run the name of its newest half, and the newest half is whatever the newest
- * the name of its newest half, and the newest half is whatever the newest page happened to start
+ * page started with -- so an active session renames its tool runs every time it is reopened. A seq
- * with -- so an active session renames its tool runs every time it is reopened, and an anchor
+ * is the server's own numbering, assigned once and never moved.
- * naming one is never found. A seq is the server's own numbering, assigned once and never moved.
  *
- * [unit] is which unit of the row the viewport started at -- see [TranscriptUnit.ordinal] -- and
+ * [unit] is which unit of the row the viewport started at and [offset] how far that unit was
- * [offset] how far that unit was scrolled past the viewport's newest edge, in pixels. A seq alone
+ * scrolled past the viewport's newest edge. A seq alone is not a place: a reply is one seq and can
- * is not a place: a reply is one seq and can be forty blocks long, and a reader stopped halfway
+ * be forty blocks long.
- * down it is put back at that block, not at the reply.
  */
 data class ScrollAnchor(val seq: Long, val offset: Int, val unit: Int = 0)
 
 /**
  * On this device rather than on the backend, which is where this app otherwise keeps state so every
  * device sees it. Scroll position is the same exception a draft is: it is where the phone in
- * somebody's hand is pointed, and having one device jump because another was scrolled would be a
+ * somebody's hand is pointed.
- * surprise rather than a convenience.
  */
 fun loadScrollAnchor(context: Context, sessionId: String): ScrollAnchor? {
     val stored =
@@ -36,8 +33,8 @@ fun loadScrollAnchor(context: Context, sessionId: String): ScrollAnchor? {
     val fields = stored.split(':')
     val seq = fields.getOrNull(0)?.toLongOrNull() ?: return null
     val offset = fields.getOrNull(1)?.toIntOrNull() ?: return null
-    // Positions saved before the unit was recorded name the row's oldest unit, which is the
+    // Positions saved before the unit was recorded name the row's oldest unit, which is the closest
-    // closest older place -- the same choice [unitIndexFor] makes when a unit is gone.
+    // older place -- the same choice [unitIndexFor] makes when a unit is gone.
     return ScrollAnchor(seq, offset, fields.getOrNull(2)?.toIntOrNull() ?: 0)
 }
 
@@ -45,9 +42,8 @@ fun loadScrollAnchor(context: Context, sessionId: String): ScrollAnchor? {
  * Records where [sessionId] is being read, or forgets it when [anchor] is null.
  *
  * The path out is reading to the newest end, which is what the caller passes null for: a session
- * left at the bottom has nothing to restore and should open at the bottom, which is also the cheap
+ * left at the bottom has nothing to restore. A session *deleted* while it held an anchor leaves its
- * case. A session *deleted* while it held an anchor leaves its key behind, for the reason and at
+ * key behind, for the reason and at the cost `Drafts.kt` describes.
- * the cost `Drafts.kt` describes.
  */
 fun saveScrollAnchor(context: Context, sessionId: String, anchor: ScrollAnchor?) {
     context.getSharedPreferences(ANCHORS, Context.MODE_PRIVATE).edit {

app/androidApp/src/main/kotlin/com/example/aiapp/ServerConfig.kt

@@ -14,10 +14,9 @@ typealias ServerSettings = com.example.wgapplink.ServerSettings
 /**
  * This app's enrollment, which is the whole of what is product-specific about it.
  *
- * Both values are load-bearing and neither may be changed casually. The scheme is what routes a
+ * Both values are load-bearing. The scheme is what routes a scanned QR here rather than to Dev
- * scanned QR here rather than to Dev Updater, and the key alias names the Android Keystore key the
+ * Updater, and the key alias names the Android Keystore key the token is already sealed under on
- * token is already sealed under on every enrolled phone -- changing it would leave those phones
+ * every enrolled phone -- changing it would leave those phones reading as not enrolled.
- * reading as not enrolled, with no error to explain why.
  */
 private val store = ServerStore(scheme = "aiapp", keyAlias = "aiapp-token-key")
 

app/androidApp/src/main/kotlin/com/example/aiapp/SessionAlerts.kt

@@ -33,16 +33,14 @@ import androidx.lifecycle.repeatOnLifecycle
 /**
  * A session wanting attention, said over the app rather than through Android's drawer.
  *
- * Two places can carry the same fact and only one of them is right at a time. A row in the shade is
+ * Two places can carry the same fact and only one is right at a time. A row in the shade is for
- * for somebody looking at something else: it makes a sound, it waits however long it has to, and
+ * somebody looking at something else: it makes a sound, it waits however long it has to, and acting
- * acting on it means leaving whatever they were doing. Somebody with this app open needs none of
+ * on it means leaving whatever they were doing. Somebody with this app open needs none of that. So
- * that -- they are already here, and what a tap on the notification would have done is what a tap
+ * while these are on screen the stream is delivered here instead, which is arranged by the
- * on this does. So while these are on screen the stream is delivered here instead, which is
+ * collection below and nothing else.
- * arranged by the collection below and nothing else; see `NotificationService.forTheScreen`.
  *
- * A banner can go three ways, and each is somebody deciding something different: tapped, which
+ * A banner can go three ways, each somebody deciding something different: tapped, which opens the
- * opens the session; pushed off either side; or left alone, in which case it goes by itself when
+ * session; pushed off either side; or left alone, in which case it goes when the bar runs out.
- * the bar across its foot runs out.
  */
 @Composable
 fun SessionAlerts(onOpen: (SessionOpenRequest) -> Unit, modifier: Modifier = Modifier) {
@@ -58,28 +56,26 @@ fun SessionAlerts(onOpen: (SessionOpenRequest) -> Unit, modifier: Modifier = Mod
                     arrivals++
                     val alert = SessionAlert(notification, arrivals)
                     // One banner per session, replacing that session's own -- the same rule the
-                    // drawer follows, and for the same reason: a session that finished and then
+                    // drawer follows: a session that finished and then asked a question is one
-                    // asked a question is one thing to know about, the question. It keeps its
+                    // thing to know about, the question. It keeps its place in the queue rather
-                    // place in the queue rather than moving to the end, because the reader may
+                    // than moving to the end, because the reader may already be reaching for it.
-                    // already be reaching for it.
                     val already = queue.indexOfFirst {
                         it.notification.sessionId == notification.sessionId
                     }
                     if (already >= 0) queue[already] = alert else queue.add(alert)
                 }
             } finally {
-                // Leaving the app hands the job back to the drawer, so nothing arriving while it
+                // Leaving the app hands the job back to the drawer, so nothing arriving while it is
-                // is away is lost. What would be lost is the truth of what is already up: these
+                // away is lost. What would be lost is the truth of what is already up: these say a
-                // say a session wants somebody *now*, and one still sitting here on a return
+                // session wants somebody *now*, and one still sitting here on a return several
-                // several minutes later is a claim nobody checked. Frozen, too -- Compose stops
+                // minutes later is a claim nobody checked. Frozen, too -- Compose stops the clock
-                // the clock with the window, so the timer that was going to retire it has been
+                // with the window.
-                // standing still the whole time.
                 queue.clear()
             }
         }
     }
-    // Oldest at the top, so a new one appears below the ones already being read instead of
+    // Oldest at the top, so a new one appears below the ones already being read instead of shoving
-    // shoving them down the screen mid-reach.
+    // them down the screen mid-reach.
     Column(modifier.fillMaxWidth().padding(8.dp)) {
         queue.forEach { alert ->
             key(alert.arrival) {
@@ -103,9 +99,7 @@ private data class SessionAlert(val notification: SessionNotification, val arriv
  * One banner: what wants attention, and how long this has left to say so.
  *
  * The bar and the going away are one value rather than a bar beside a timer, because two of them
- * would be two accounts of the same countdown and only one can be the one that fires. What is drawn
+ * would be two accounts of the same countdown and only one can be the one that fires.
- * is therefore the thing that decides, which is the only arrangement where a bar that has emptied
- * cannot be sitting under a banner that is still there.
  */
 @Composable
 private fun AlertBanner(alert: SessionAlert, onOpen: () -> Unit, onGone: () -> Unit) {
@@ -135,9 +129,7 @@ private fun AlertBanner(alert: SessionAlert, onOpen: () -> Unit, onGone: () -> U
                 ),
             // Outlined, because the step it needs to make is not one this palette can make with a
             // tint: the card under a banner on the session list is the same surface, so a banner
-            // relying on colour alone reads as one more row that happens to be in the way. The
+            // relying on colour alone reads as one more row in the way. The border is the one cue.
-            // border is the one cue, and the elevation beside it is the platform's shadow rather
-            // than a second tint -- Material draws no tonal overlay over a container stated here.
             border = BorderStroke(1.dp, MaterialTheme.colorScheme.outline),
             elevation = CardDefaults.cardElevation(defaultElevation = 6.dp),
         ) {
@@ -145,8 +137,8 @@ private fun AlertBanner(alert: SessionAlert, onOpen: () -> Unit, onGone: () -> U
                 Text(
                     alert.notification.title,
                     style = MaterialTheme.typography.titleSmall,
-                    // One line, cut at the tail: a session is identified by the start of its
+                    // One line, cut at the tail: a session is identified by the start of its name,
-                    // name, and a banner that grew with the name would move the one below it.
+                    // and a banner that grew with the name would move the one below it.
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
                 )
@@ -163,9 +155,8 @@ private fun AlertBanner(alert: SessionAlert, onOpen: () -> Unit, onGone: () -> U
             LinearProgressIndicator(
                 progress = { life.value },
                 // Blue because it is reporting how much of something is left rather than passing
-                // judgement on it -- the reason `progressColor` exists. Stated beside the track,
+                // judgement on it. Stated beside the track, which is the card's own colour so that
-                // which is the card's own colour so that the spent part reads as empty rather
+                // the spent part reads as empty rather than as a second bar.
-                // than as a second bar.
                 color = progressColor,
                 trackColor = MaterialTheme.colorScheme.surfaceContainerHigh,
                 drawStopIndicator = {},
@@ -180,7 +171,6 @@ private fun AlertBanner(alert: SessionAlert, onOpen: () -> Unit, onGone: () -> U
  * How long a banner stays if nobody touches it.
  *
  * Long enough to read a session name and a line, short enough that a stack of them clears itself
- * while somebody is still on the screen that produced them. The bar makes the number visible, so
+ * while somebody is still on the screen that produced them. The bar makes the number visible.
- * this is a duration the reader can watch rather than one they have to learn.
  */
 private const val ALERT_LIFE_MS = 6_000

app/androidApp/src/main/kotlin/com/example/aiapp/SessionImage.kt

@@ -49,10 +49,9 @@ data class SessionBitmap(val bitmap: ImageBitmap?, val failed: Boolean)
 
 /**
  * Fetches (authenticated, pinned) and decodes one transcript image, remembered per ref so scrolling
- * does not refetch.
+ * does not refetch. Shared by the transcript's images and the composer's pending attachments,
- *
+ * because the fetch, the decode and the two-state answer are one block of logic that had been
- * Shared by the transcript's images and the composer's pending attachments, because the fetch, the
+ * written twice.
- * decode and the two-state answer are one block of logic that had been written twice.
  */
 @Composable
 fun rememberSessionBitmap(settings: ServerSettings, sessionId: String, ref: String): SessionBitmap {
@@ -75,15 +74,12 @@ fun rememberSessionBitmap(settings: ServerSettings, sessionId: String, ref: Stri
  * An image in the transcript: a fixed-height thumbnail that opens full screen.
  *
  * The height is decided before the bytes arrive and never changes. An image row that grew when it
- * finished loading pushed everything below it, so a transcript being read scrolled itself while
+ * finished loading pushed everything below it, so a transcript being read scrolled itself -- and in
- * somebody was looking at it -- and in a bottom-anchored list, images loading above the viewport
+ * a bottom-anchored list, images loading above the viewport moved the text under the reader's eyes.
- * moved the text under the reader's eyes. Reserving the final height makes loading invisible, which
- * is what it should be.
  *
  * Four lines of body text, so a screenshot reads as an attachment beside the conversation rather
- * than as a page of its own. Full size is one tap away -- but the full-size view itself is not
+ * than as a page of its own. The full-size view itself is not here: [onOpen] hands the ref to the
- * here. [onOpen] hands the ref to the screen, which draws [SessionImageViewer] outside the list;
+ * screen, which draws [SessionImageViewer] outside the list.
- * see that function for the reason.
  */
 @Composable
 fun SessionImage(
@@ -97,9 +93,8 @@ fun SessionImage(
     val heightPx = with(LocalDensity.current) { height.roundToPx() }
     Box(Modifier.fillMaxWidth().height(height), contentAlignment = Alignment.CenterStart) {
         when (val image = bitmap) {
-            // Two states, not one: an image still arriving and an image that will never arrive
+            // Two states, not one: an image still arriving and an image that will never arrive look
-            // look nothing alike to a reader who can do something about the second. So one gets a
+            // nothing alike to a reader who can do something about the second.
-            // spinner in the space the picture is about to fill, and the other gets words.
             null ->
                 if (failed) {
                     Text(
@@ -130,15 +125,12 @@ fun SessionImage(
  * `Read` on its own is a row of one call, and the moment the next call arrives the two become a
  * group -- a different composable in a different part of the tree, so everything the old subtree
  * remembered goes, the dialog included. Somebody looking at a screenshot was thrown back to the
- * transcript because the session made another tool call. The same happens to a row regrouped by a
+ * transcript because the session made another tool call.
- * page of history landing.
  *
- * Held by the screen, none of that reaches it: what is open is a property of the screen, not of
+ * Held by the screen, none of that reaches it: what is open is a property of the screen.
- * whichever row happened to draw the thumbnail.
  *
  * The cost is one fetch, since the thumbnail's decoded bitmap belongs to a row this does not go
- * through. Paid deliberately rather than plumbed around: it is one request for a picture somebody
+ * through. Paid deliberately: it is one request for a picture somebody asked to see.
- * asked to see, and the loading and unavailable states below are the same two the thumbnail draws.
  */
 @Composable
 fun SessionImageViewer(
@@ -157,9 +149,9 @@ fun SessionImageViewer(
             contentAlignment = Alignment.Center,
         ) {
             when (val image = bitmap) {
-                // Two states, not one, exactly as the thumbnail has them: still coming, and never
+                // Two states, not one, exactly as the thumbnail has them. Stated in white because
-                // coming. Stated in white because this box paints its own black behind them and a
+                // this box paints its own black behind them and a theme colour would be picked
-                // theme colour would be picked against a surface that is not there.
+                // against a surface that is not there.
                 null ->
                     if (failed) {
                         Text(
@@ -170,8 +162,7 @@ fun SessionImageViewer(
                     } else {
                         // The whole dialog is the area this picture is about to fill, so the
                         // spinner sits in the middle of it. White for the same reason the words
-                        // beside it are: this box paints its own black, and a theme colour would
+                        // beside it are.
-                        // be chosen against a surface that is not there.
                         CircularProgressIndicator(color = Color.White)
                     }
                 else -> ZoomableImage(image)
@@ -185,11 +176,10 @@ fun SessionImageViewer(
  *
  * A square of the row's own height rather than the full width of the transcript: the height is what
  * [SessionImage] reserves and the width is not known until the bytes arrive, so a full-width
- * placeholder would promise a picture wider than most of them turn out to be. Square is the closest
+ * placeholder would promise a picture wider than most turn out to be.
- * thing to "the size of it" that can be drawn before knowing.
  *
- * Tinted, so the reader can see that something is being kept for a picture. That is also what
+ * Tinted, so the reader can see that something is being kept for a picture -- which is also what
- * distinguishes it from the failure beside it, which is words on the ordinary surface.
+ * distinguishes it from the failure beside it, words on the ordinary surface.
  */
 @Composable
 private fun LoadingImage(height: Dp) {
@@ -210,8 +200,8 @@ private val LOADING_SPINNER = 24.dp
  * Four lines of the body style the transcript is set in.
  *
  * Measured from the type rather than written as a dp, so it stays four lines when the text size
- * changes -- including when the reader has scaled fonts up, which is exactly when a hardcoded
+ * changes -- including when the reader has scaled fonts up, which is when a hardcoded height is
- * height would be wrong.
+ * wrong.
  */
 @Composable
 private fun thumbnailHeight(): Dp {
@@ -226,8 +216,7 @@ private fun thumbnailHeight(): Dp {
  * Nearest neighbour when the image is being enlarged, smooth when it is being shrunk.
  *
  * A small image blown up with interpolation turns into a blur that hides what it is -- the same
- * image with hard pixel edges stays readable. Shrinking wants the opposite, so this is a decision
+ * image with hard pixel edges stays readable. Shrinking wants the opposite.
- * per image rather than a preference set once.
  */
 private fun enlargingFilter(sourceHeight: Int, drawnHeight: Int): FilterQuality =
     if (sourceHeight < drawnHeight) FilterQuality.None else FilterQuality.High
@@ -237,7 +226,7 @@ private fun enlargingFilter(sourceHeight: Int, drawnHeight: Int): FilterQuality
  *
  * Inside a dialog rather than a screen -- see [SessionImageViewer] -- so the platform's back
  * gesture returns to the transcript instead of leaving the app. It opens fitted, the whole image
- * visible, which is the thing a reader wants first; zoom is theirs from there.
+ * visible.
  */
 @Composable
 private fun ZoomableImage(image: ImageBitmap) {

app/androidApp/src/main/kotlin/com/example/aiapp/SessionListScreen.kt

@@ -53,24 +53,19 @@ fun SessionListScreen(
     var listState by remember { mutableStateOf<LoadState<List<SessionSummary>>>(LoadState.Loading) }
     var confirmingDelete by remember { mutableStateOf<SessionSummary?>(null) }
 
-    // Failures that belong to one session rather than to the list, keyed by
+    // Failures that belong to one session rather than to the list, keyed by its id and shown on its
-    // its id and shown on its own card. The two scopes are decided by
+    // own card. The two scopes are decided by whether the server answered: it answered and refused,
-    // whether the server answered: it answered and refused, so this says
+    // so this says nothing about the other rows.
-    // nothing about the other rows, where a server that has stopped
-    // answering leaves every row stale and is `listState`'s to report.
     //
-    // Cleared on the next successful load below -- an entry outlives its
+    // Cleared on the next successful load below -- an entry outlives its session otherwise.
-    // session otherwise, and would reappear against whatever the phone
-    // fetched next.
     var deleteErrors by remember { mutableStateOf<Map<String, String>>(emptyMap()) }
 
-    // Which sessions have a delete in flight. A set of ids rather than a flag on the row,
+    // Which sessions have a delete in flight. A set of ids rather than a flag on the row, because
-    // because the rows are rebuilt from whatever the server last said and this belongs to the
+    // the rows are rebuilt from whatever the server last said and this belongs to the request.
-    // request rather than to the session.
     var deleting by remember { mutableStateOf<Set<String>>(emptySet()) }
 
-    // This phone's copies of these sessions' transcripts, pruned from here because this is where
+    // This phone's copies of these sessions' transcripts, pruned from here because this is where a
-    // a session stops existing. See TranscriptCache.
+    // session stops existing. See TranscriptCache.
     val context = LocalContext.current
     val transcriptCache = remember(settings) { TranscriptCache(cacheRoot(context, settings)) }
 
@@ -83,10 +78,9 @@ fun SessionListScreen(
                         withContext(Dispatchers.IO) { LoadState.Loaded(fetchSessions(settings)) }
                     deleteErrors = emptyMap()
                     // The path out for a cached transcript whose session was deleted somewhere
-                    // else -- from another device, or at the backend. This list is the only place
+                    // else. This list is the only place that ever learns the full set. On the
-                    // that ever learns the full set, and what the residue costs here is megabytes
+                    // answer rather than in `finally`: a list that failed to arrive says nothing
-                    // rather than a draft's few bytes. On the answer rather than in `finally`: a
+                    // about which sessions exist.
-                    // list that failed to arrive says nothing about which sessions exist.
                     withContext(Dispatchers.IO) {
                         transcriptCache.retainOnly(loaded.value.map { it.id }.toSet())
                     }
@@ -103,12 +97,9 @@ fun SessionListScreen(
         Column(Modifier.fillMaxSize().padding(16.dp)) {
             when (val state = listState) {
                 is LoadState.Loading -> CircularProgressIndicator()
-                // The message as Api.kt wrote it, with nothing added: it is
+                // The message as Api.kt wrote it, with nothing added: it is already a whole
-                // already a whole sentence naming the address and what to
+                // sentence naming the address and what to check, so a prefix here read "Couldn't
-                // check, so a prefix here read "Couldn't reach the server:
+                // reach the server: Couldn't reach the server at ...".
-                // Couldn't reach the server at ...". It was also a guess --
-                // a delete that the server itself refused had reached it
-                // fine.
                 is LoadState.Error ->
                     Text(
                         state.message,
@@ -122,8 +113,7 @@ fun SessionListScreen(
                             color = MaterialTheme.colorScheme.onSurfaceVariant,
                         )
                     }
-                    // Awaiting-answer first (the point of the screen), then
+                    // Awaiting-answer first (the point of the screen), then most recently active.
-                    // most recently active.
                     val ordered =
                         state.value.sortedWith(
                             compareByDescending<SessionSummary> { it.status == "awaitingInput" }
@@ -155,40 +145,37 @@ fun SessionListScreen(
 
     confirmingDelete?.let { session ->
         // Reset per session, so a toggle turned on for one conversation is not still on for the
-        // next one somebody opens this dialog for. Off to begin with: see [deleteSession].
+        // next. Off to begin with: see [deleteSession].
         var alsoDeleteForeign by remember(session.id) { mutableStateOf(false) }
         AlertDialog(
             onDismissRequest = { confirmingDelete = null },
             title = { Text("Delete \"${session.title}\"?") },
             text = {
                 // Two different acts behind one button, so it says which one this is. What
-                // separates them is whether the *driver* keeps its own record of the
+                // separates them is whether the *driver* keeps its own record of the conversation
-                // conversation -- the Claude Code CLI does, under ~/.claude/projects, whether
+                // -- the Claude Code CLI does, whether this app spawned the session or imported it;
-                // this app spawned the session or imported it; echo and llama.cpp do not, and
+                // echo and llama.cpp do not.
-                // for those the app's transcript is the only copy there is.
                 //
                 // This used to branch on `imported`, above a comment asserting that "a session
-                // started here has no copy anywhere". That was simply false for every
+                // started here has no copy anywhere". That was false for every claude-cli session
-                // claude-cli session this app spawned, and the two warnings disagreed about
+                // this app spawned, and getting it wrong in that direction is the expensive one:
-                // sessions that were equally recoverable. Getting it wrong in that direction
+                // "this can't be undone", said of something that can, spends the credibility the
-                // is the expensive one: "this can't be undone", said of something that can,
+                // sentence needs.
-                // spends the credibility the sentence needs on the sessions where it is true.
                 //
-                // Neither branch promises a restore. The recoverable one says what is known --
+                // Neither branch promises a restore. The recoverable one says what is known -- the
-                // the driver keeps its own record -- rather than that the file is still there,
+                // driver keeps its own record -- rather than that the file is still there, and it
-                // which nothing here checked; and it names what goes either way, because this
+                // names what goes either way, because this app's transcript holds images, peer
-                // app's transcript holds images, peer messages and commands that the CLI's own
+                // messages and commands the CLI's own record never had.
-                // record never had.
                 Column {
                     Text(
                         when {
                             !session.keepsOwnTranscript ->
                                 "Kills the process and deletes the conversation. Nothing else " +
                                     "keeps a copy, so this can't be undone."
-                            // The sentence below is the one the toggle makes false, which is why
+                            // The sentence below is the one the toggle makes false, which is why it
-                            // it is written twice rather than appended to: leaving "should still
+                            // is written twice rather than appended to: leaving "should still be
-                            // be there to import again" on screen beside a switch that removes it
+                            // there to import again" on screen beside a switch that removes it is
-                            // is the reassurance being read at the moment it stops being true.
+                            // the reassurance being read at the moment it stops being true.
                             alsoDeleteForeign ->
                                 "Kills the process and deletes both copies of the conversation: " +
                                     "this app's, and Claude Code's own transcript on the " +
@@ -203,12 +190,12 @@ fun SessionListScreen(
                     )
                     // Only where there is a second copy to decide about. Absent rather than
                     // disabled, because this is not a capability being withheld: for echo and
-                    // llama.cpp there is no other transcript, and a switch offering to delete
+                    // llama.cpp there is no other transcript, and a switch offering to delete one
-                    // one would be asking about something that does not exist.
+                    // would be asking about something that does not exist.
                     if (session.keepsOwnTranscript) {
                         Spacer(Modifier.height(16.dp))
-                        // Its own row rather than beside the paragraph: a switch is taller than
+                        // Its own row rather than beside the paragraph: a switch is taller than a
-                        // a line of text and re-centres whatever shares a row with it.
+                        // line of text and re-centres whatever shares a row with it.
                         Row(verticalAlignment = Alignment.CenterVertically) {
                             Text(
                                 "Delete Claude Code's transcript too",
@@ -229,8 +216,7 @@ fun SessionListScreen(
                     onClick = {
                         confirmingDelete = null
                         // Marked here rather than after the request returns: the row has to say
-                        // something is happening to it from the moment it is asked for, which
+                        // something is happening to it from the moment it is asked for.
-                        // is the whole of what this state is for.
                         deleting = deleting + session.id
                         deleteErrors = deleteErrors - session.id
                         scope.launch {
@@ -241,10 +227,9 @@ fun SessionListScreen(
                                     // session exactly as it was, and its transcript with it.
                                     transcriptCache.session(session.id).purge()
                                 }
-                                // Only this row, and only what changed. Refetching the list
+                                // Only this row, and only what changed. Refetching the list instead
-                                // instead put every other session back through loading and
+                                // put every other session back through loading and handed the
-                                // handed the reader an empty screen -- to report on something
+                                // reader an empty screen, to report on something never in doubt.
-                                // that was never in doubt.
                                 val loaded = listState
                                 if (loaded is LoadState.Loaded) {
                                     listState =
@@ -263,8 +248,8 @@ fun SessionListScreen(
                         }
                     }
                 ) {
-                    // Coloured by consequence: this takes something away, and does so wherever
+                    // Coloured by consequence: this takes something away, and does so wherever it
-                    // it appears -- the same rule the import screen's Delete follows.
+                    // appears -- the same rule the import screen's Delete follows.
                     Text("Delete", color = MaterialTheme.colorScheme.error)
                 }
             },
@@ -286,8 +271,7 @@ private fun SessionCard(
      *
      * Suspended rather than removed while it is -- see [BusyItem] -- which says the row is on its
      * way out without claiming it has gone: a row removed the moment Delete is pressed is a promise
-     * about a request that has not been answered yet, and putting it back when the server refuses
+     * about a request that has not been answered yet.
-     * is worse than never having taken it away.
      */
     deleting: Boolean,
     onOpen: () -> Unit,
@@ -295,9 +279,9 @@ private fun SessionCard(
 ) {
     BusyItem(label = if (deleting) "deleting" else null) {
         Card(
-            // Off while the delete is in flight: a card that still opens a session it is
+            // Off while the delete is in flight: a card that still opens a session it is deleting
-            // deleting is a race the reader can start by tapping. On the card rather than in
+            // is a race the reader can start by tapping. On the card rather than in [BusyItem],
-            // [BusyItem], which leaves gestures alone so the list still scrolls.
+            // which leaves gestures alone so the list still scrolls.
             Modifier.fillMaxWidth()
                 .combinedClickable(
                     enabled = !deleting,
@@ -320,9 +304,9 @@ private fun SessionCard(
                 Spacer(Modifier.height(4.dp))
                 Row(modifier = Modifier.fillMaxWidth()) {
                     Text(
-                        // Machine, then what runs on it, then what it is set to: the same order
+                        // Machine, then what runs on it, then what it is set to: the same order and
-                        // and separator as the session screen's header and the usage dialog, so
+                        // separator as the session screen's header and the usage dialog, so one
-                        // one pair of facts is not written three ways.
+                        // pair of facts is not written three ways.
                         listOfNotNull(
                                 session.setupName,
                                 session.provider,
@@ -341,8 +325,7 @@ private fun SessionCard(
                 }
                 error?.let {
                     Spacer(Modifier.height(8.dp))
-                    // The server's own words, unprefixed, the way every other
+                    // The server's own words, unprefixed, the way every other failure is shown.
-                    // failure in this app is shown.
                     Text(
                         it,
                         style = MaterialTheme.typography.bodySmall,
@@ -362,16 +345,16 @@ fun StatusText(status: String) {
             "running" -> "running" to runningColor
             "compacting" -> "compacting" to commandColor
             "exited" -> "exited" to MaterialTheme.colorScheme.onSurfaceVariant
-            // Said in words, because it differs in kind from the others rather than in degree:
+            // Said in words, because it differs in kind from the others rather than in degree: the
-            // the session is not idle and has not exited, nobody has been able to find out
+            // session is not idle and has not exited, nobody has been able to find out which. A
-            // which. A muted colour alone would read as one of the quiet states.
+            // muted colour alone would read as one of the quiet states.
             "unknown" -> "can't tell" to MaterialTheme.colorScheme.onSurfaceVariant
             else -> status to MaterialTheme.colorScheme.onSurfaceVariant
         }
     Row(verticalAlignment = Alignment.CenterVertically) {
         if (sessionWorking(status)) {
-            // The same colour as the word beside it: the two are one signal, and a spinner in
+            // The same colour as the word beside it: the two are one signal, and a spinner in the
-            // the theme's accent says the state is something other than what the label says.
+            // theme's accent says the state is something other than what the label says.
             CircularProgressIndicator(
                 modifier = Modifier.width(14.dp).height(14.dp),
                 strokeWidth = 2.dp,

app/androidApp/src/main/kotlin/com/example/aiapp/SessionSettingsDialog.kt

@@ -39,14 +39,11 @@ import kotlinx.coroutines.withContext
  * controls and hid the thing they act on.
  *
  * The model and the permission mode are deliberately still on the session's own bar, because those
- * are changed *while* reading a turn -- "not this model, try that one" -- and a control belongs
+ * are changed *while* reading a turn -- "not this model, try that one".
- * with the thing it acts on.
  *
- * Captions are for what a control costs rather than for what it is. Each control is a labelled noun
+ * Captions are for what a control costs rather than for what it is. A paragraph under every control
- * with a switch or a field beside it, and a paragraph under every one of them made the dialog
+ * made the dialog longer than the conversation it covers -- so Notifications has none, while Move
- * longer than the conversation it covers -- so Notifications has none, while Move and Reload do,
+ * and Reload do, because what those two take away is not visible from here.
- * because what those two take away is not visible from here. Failures get their words for the same
- * reason: they are what the reader cannot work out by looking.
  */
 @Composable
 fun SessionSettingsDialog(
@@ -66,7 +63,7 @@ fun SessionSettingsDialog(
     onDismiss: () -> Unit,
     /**
      * Copies what this session costs to draw. Built by the session screen, because everything it
-     * measures is that screen's own state -- see `copyRenderReport` there.
+     * measures is that screen's own state.
      */
     onCopyRenderReport: () -> Unit,
 ) {
@@ -76,16 +73,14 @@ fun SessionSettingsDialog(
     var error by remember { mutableStateOf<String?>(null) }
     // Null until the server has been asked. The row this dialog was opened over is a snapshot of
     // whenever the list was last fetched, so drawing the switch straight from it would show a
-    // position that may have been changed since -- from here or from another device -- with
+    // position that may have been changed since. Until the answer arrives the switch is disabled
-    // nothing to say so. Until the answer arrives the switch is disabled and a spinner sits beside
+    // and a spinner sits beside it, which is what not knowing looks like.
-    // it, which is what not knowing looks like: distinguishable from off, and from a refusal.
     var notify by remember(sessionId) { mutableStateOf<Boolean?>(null) }
     var notifyError by remember { mutableStateOf<String?>(null) }
-    // Where the session works. Null until the server has been asked, for the same reason the
+    // Where the session works. Null until the server has been asked, for the same reason the switch
-    // switch above is: the row this dialog opened over is a snapshot, and a path drawn from it
+    // above is. An empty answer is a session that was never given a directory, which is not the
-    // could be one somebody changed from another device. An empty answer is a session that was
+    // same as one whose directory is unknown -- the field is only enabled once one of those is
-    // never given a directory, which is not the same as one whose directory is unknown -- the
+    // settled.
-    // field is only enabled once one of those two is settled.
     var cwd by remember(sessionId) { mutableStateOf<String?>(null) }
     var typedCwd by remember(sessionId) { mutableStateOf("") }
     var cwdError by remember { mutableStateOf<String?>(null) }
@@ -98,8 +93,8 @@ fun SessionSettingsDialog(
             cwd = fresh.cwd.orEmpty()
             typedCwd = fresh.cwd.orEmpty()
         } catch (e: ApiException) {
-            // Left unknown rather than falling back to the stale row: the switch stays
+            // Left unknown rather than falling back to the stale row: the switch stays disabled,
-            // disabled, instead of offering a position nothing confirmed.
+            // instead of offering a position nothing confirmed.
             notifyError = e.message
             notify = null
         }
@@ -131,8 +126,8 @@ fun SessionSettingsDialog(
     }
 
     // Moved optimistically so the switch answers the finger that moved it, and put back if the
-    // request is refused -- a switch that waits for a round trip reads as broken on a slow
+    // request is refused -- a switch that waits for a round trip reads as broken on a slow tunnel,
-    // tunnel, and one that stays moved after a refusal lies.
+    // and one that stays moved after a refusal lies.
     fun setNotify(wanted: Boolean) {
         val was = notify
         notify = wanted
@@ -162,7 +157,7 @@ fun SessionSettingsDialog(
                 onRenamed(chosen)
             } catch (e: ApiException) {
                 // Reported here, where it happened, because this dialog is the only place that
-                // knows a rename was attempted -- the session behind it shows nothing about it.
+                // knows a rename was attempted.
                 error = e.message
                 saving = false
             }
@@ -181,8 +176,8 @@ fun SessionSettingsDialog(
                     singleLine = true,
                     enabled = !saving,
                     modifier = Modifier.fillMaxWidth(),
-                    // The keyboard's own action does what the button does: a one-field form
+                    // The keyboard's own action does what the button does: a one-field form where
-                    // where the return key does nothing is a form people press return at anyway.
+                    // the return key does nothing is a form people press return at anyway.
                     keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
                     keyboardActions = KeyboardActions(onDone = { save() }),
                 )
@@ -207,8 +202,8 @@ fun SessionSettingsDialog(
                         enabled = notify != null,
                     )
                 }
-                // Beside the switch that failed, not with the rename's error: they are two
+                // Beside the switch that failed, not with the rename's error: they are two requests
-                // requests and a reader has to be able to tell which one the server refused.
+                // and a reader has to be able to tell which one the server refused.
                 notifyError?.let {
                     Text(
                         it,
@@ -225,9 +220,9 @@ fun SessionSettingsDialog(
                         value = typedCwd,
                         onValueChange = { typedCwd = it },
                         label = { Text("Working directory") },
-                        // What the field cannot say by being empty: a session that was never
+                        // What the field cannot say by being empty: a session that was never given
-                        // given one starts wherever its launcher does, and this names that
+                        // one starts wherever its launcher does, and this names that rather than
-                        // rather than showing a path nobody chose.
+                        // showing a path nobody chose.
                         placeholder = { Text("wherever the session was started") },
                         singleLine = true,
                         enabled = cwd != null && !movingCwd,
@@ -247,9 +242,8 @@ fun SessionSettingsDialog(
                     }
                 }
                 // The whole of what pressing Move does, where it is about to be pressed. A
-                // directory is settled when the process is spawned, so there is no changing one
+                // directory is settled when the process is spawned, so it is ended and the next
-                // under a running session -- it is ended, and the next thing said to the session
+                // thing said to the session starts it in the new place.
-                // starts it in the new place.
                 Text(
                     "Moving stops the session's process. It starts again in the new directory " +
                         "with the next message, or with Start.",
@@ -269,10 +263,10 @@ fun SessionSettingsDialog(
                     modifier = Modifier.fillMaxWidth(),
                 ) {
                     Text("Transcript", modifier = Modifier.weight(1f))
-                    // The size is what the button discards, and the unknown state is drawn
+                    // The size is what the button discards, and the unknown state is drawn rather
-                    // rather than guessed: a spinner while the directory is being measured, and
+                    // than guessed: a spinner while the directory is being measured, and words when
-                    // words when there is nothing there, because "nothing cached" and "0 B" read
+                    // there is nothing there, because "nothing cached" and "0 B" read as different
-                    // as different claims.
+                    // claims.
                     when {
                         cachedBytes == null ->
                             CircularProgressIndicator(
@@ -325,8 +319,8 @@ fun SessionSettingsDialog(
                 }
             }
         },
-        // Disabled rather than absent while there is nothing to save: a button that comes and
+        // Disabled rather than absent while there is nothing to save: a button that comes and goes
-        // goes makes its own presence the signal, and its absence cannot say why.
+        // makes its own presence the signal, and its absence cannot say why.
         confirmButton = {
             TextButton(onClick = { save() }, enabled = changed && !saving) {
                 Text(if (saving) "Saving..." else "Save")

app/androidApp/src/main/kotlin/com/example/aiapp/SessionUsageBar.kt

@@ -34,20 +34,19 @@ sealed class SessionUsage {
     /**
      * This machine meters nothing, so there is no window to show.
      *
-     * Separate from [Unavailable], and the distinction is the whole point: a session on `echo` or
+     * Separate from [Unavailable], and the distinction is the point: a session on `echo` or on a
-     * on a local llama.cpp has no paid quota at all, which is a fact about how it was set up and
+     * local llama.cpp has no paid quota at all, which is a fact about how it was set up and not a
-     * not a failure to find something out. The backend never asks such a machine, so it returns no
+     * failure to find something out. The backend never asks such a machine, and reading that
-     * snapshot for it -- and reading that silence as "couldn't find out" is exactly the mistake of
+     * silence as "couldn't find out" is answering with the nearest available word.
-     * answering with the nearest available word. Drawn as nothing, because there is nothing.
      */
     data object NotMetered : SessionUsage()
 
     /**
      * The question could not be answered, and why.
      *
-     * Its own state because "we couldn't find out" and "none of it is used" are the pair that must
+     * Its own state because "we couldn't find out" and "none of it is used" must never share an
-     * never share an appearance: a bar sitting at zero because a machine is unreachable reads as
+     * appearance: a bar sitting at zero because a machine is unreachable reads as plenty of
-     * plenty of headroom, which is the opposite of the truth.
+     * headroom.
      */
     data class Unavailable(val why: String) : SessionUsage()
 }
@@ -59,17 +58,14 @@ private const val REFRESH_MS = 60_000L
  * One poll of every machine's limits, and the handle to ask again.
  *
  * A screen shows this answer in more than one place -- the bar under the session header, the colour
- * of the button beside it, and the dialog that button opens -- and each of those used to fetch for
+ * of the button beside it, and the dialog that button opens -- and each used to fetch for itself.
- * itself. Two fetches say one thing twice and then disagree about it: the bar's copy can be a whole
+ * Two fetches say one thing twice and then disagree: the bar's copy can be a whole refresh interval
- * refresh interval old when the dialog opens with a fresh one, so the header read 42% while the
+ * old when the dialog opens with a fresh one, so the header read 42% while the screen over it read
- * screen over it read 47%, about a number somebody is deciding on. One feed per screen, and
+ * 47%.
- * [refresh] moves both.
  */
 class UsageFeed(
     val snapshots: LoadState<List<UsageSnapshot>>,
-    /**
+    /** A fetch is outstanding. Only ever true over an answer already shown. */
-     * A fetch is outstanding. Only ever true over an answer already shown; see [rememberUsageFeed].
-     */
     val refreshing: Boolean,
     /** Ask the backend again now. The dialog's refresh button; the poll does it on its own. */
     val refresh: () -> Unit,
@@ -93,15 +89,15 @@ class UsageFeed(
 fun rememberUsageFeed(settings: ServerSettings): UsageFeed {
     var snapshots by remember { mutableStateOf<LoadState<List<UsageSnapshot>>>(LoadState.Loading) }
     var refreshing by remember { mutableStateOf(true) }
-    // Bumped to ask again now. The poll below restarts from the new value, so a manual refresh
+    // Bumped to ask again now. The poll below restarts from the new value, so a manual refresh also
-    // also resets the countdown to the next one rather than leaving one due immediately after.
+    // resets the countdown rather than leaving one due immediately after.
     var asked by remember { mutableIntStateOf(0) }
     LaunchedEffect(asked) {
         while (true) {
             refreshing = true
-            // Replaces the answer only once the next one is in hand: dropping back to Loading
+            // Replaces the answer only once the next one is in hand: dropping back to Loading would
-            // would blank a bar somebody is reading for the length of a round trip, and what was
+            // blank a bar somebody is reading for the length of a round trip, and what was on
-            // on screen is still the last thing the machine actually said.
+            // screen is still the last thing the machine actually said.
             snapshots =
                 try {
                     LoadState.Loaded(withContext(Dispatchers.IO) { fetchUsage(settings) })
@@ -121,13 +117,11 @@ fun rememberUsageFeed(settings: ServerSettings): UsageFeed {
  * Worst rather than the five-hour one, because the button it colours opens *all* of them, and a
  * blue icon over a weekly quota at 97% would be the interface answering a question nobody asked.
  * Taken over however many windows came back rather than the three Claude sends today -- the backend
- * deliberately passes windows it does not recognise straight through, so a fourth one is a thing
+ * passes windows it does not recognise straight through.
- * that happens rather than a thing to notice later.
  *
  * Every state that is not a measurement takes the ordinary control colour instead. That is the
  * point where colour stops being able to help: blue is the low end of a scale here, so colouring an
- * unknown blue would say "measured, and fine" about a machine nobody could reach. The dialog behind
+ * unknown blue would say "measured, and fine" about a machine nobody could reach.
- * the button is where those say, in words, which one they are.
  */
 @Composable
 fun usageGlyphColour(usage: SessionUsage): Color =
@@ -145,18 +139,17 @@ fun usageGlyphColour(usage: SessionUsage): Color =
  * going, and it was a screen away from the place that decision gets made. It reports on this
  * session's machine alone -- the dialog is still where every machine is compared.
  *
- * What it shows is the paid service's own metering, fetched from the machine that holds the
+ * What it shows is the paid service's own metering, never derived from what this app has watched go
- * account. It is never derived from what this app has watched go past: the transcript's token
+ * past: the transcript's token counts are a different quantity, measured differently, and a bar
- * counts are a different quantity, measured differently, and a bar shaped like a quota gauge built
+ * built out of them would be a guess wearing a measurement's clothes.
- * out of them would be a guess wearing a measurement's clothes.
  */
 @Composable
 fun SessionUsageBar(usage: SessionUsage, modifier: Modifier = Modifier) {
     DebugStats.count("usage bar recomposed")
     // The countdown moves even when the numbers do not, so it is driven by a clock of its own
     // rather than recomputed at draw time: a percentage that comes back unchanged is an equal
-    // value, Compose skips the recomposition, and a "left" that only ticked when the quota
+    // value, Compose skips the recomposition, and a "left" that only ticked when the quota moved
-    // happened to move would sit at a stale figure for hours.
+    // would sit at a stale figure for hours.
     var now by remember { mutableStateOf(OffsetDateTime.now()) }
     LaunchedEffect(Unit) {
         while (true) {
@@ -165,8 +158,8 @@ fun SessionUsageBar(usage: SessionUsage, modifier: Modifier = Modifier) {
         }
     }
 
-    // Nothing at all for a machine that meters nothing: a row saying "unknown" there would
+    // Nothing at all for a machine that meters nothing: a row saying "unknown" there would report a
-    // report a problem about a setup somebody chose, on every screen, forever.
+    // problem about a setup somebody chose, on every screen, forever.
     if (usage is SessionUsage.NotMetered) {
         return
     }
@@ -222,9 +215,8 @@ private fun UsageNote(text: String) {
  * The percentage on its own does not answer the question it gets asked, which is whether to start
  * something now; 80% with twenty minutes to go and 80% with four hours to go are opposite answers.
  *
- * The window's end has two missing cases and they are worded differently on purpose; see
+ * The window's end has two missing cases, worded differently on purpose; see [WindowEnd]. A window
- * [WindowEnd]. A window that is not running gets the percentage and nothing else, because there is
+ * that is not running gets the percentage and nothing else.
- * no countdown to report and inventing one would be the same fault as inventing the number.
  */
 private fun fiveHourLabel(window: UsageWindow, now: OffsetDateTime): String {
     val percent = "${window.percent.toInt()}%"
@@ -244,8 +236,7 @@ private fun fiveHourLabel(window: UsageWindow, now: OffsetDateTime): String {
 /**
  * One machine's snapshot, out of every machine's.
  *
- * Every way of having *failed* to get numbers is [SessionUsage.Unavailable] with the reason in it:
+ * Every way of having *failed* to get numbers is [SessionUsage.Unavailable] with the reason in it.
- * a machine nobody logged into, one that could not be reached, a snapshot that came back empty.
  * None of them may look like zero, and none may look like [SessionUsage.NotMetered], which is the
  * machine having no quota rather than the question going unanswered.
  */

app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt

@@ -47,15 +47,14 @@ fun SettingsScreen(
     val context = LocalContext.current
     var host by remember { mutableStateOf(existing?.host ?: "10.66.0.1") }
     var port by remember { mutableStateOf((existing?.port ?: 8443).toString()) }
-    // Never pre-filled from the stored token: this screen shouldn't be a
+    // Never pre-filled from the stored token: this screen shouldn't be a way to read the credential
-    // way to read the credential back off the device.
+    // back off the device.
     var token by remember { mutableStateOf("") }
     var error by remember { mutableStateOf<String?>(null) }
 
     val scanLauncher =
         rememberLauncherForActivityResult(ScanContract()) { result: ScanIntentResult ->
-            // Null contents means the user backed out of the scanner -- not an
+            // Null contents means the user backed out of the scanner -- not an error.
-            // error, so nothing to report.
             val contents = result.contents ?: return@rememberLauncherForActivityResult
             val settings = parseEnrollmentUri(contents.toUri())
             if (settings == null) {
@@ -83,8 +82,8 @@ fun SettingsScreen(
             // left-pointing arrow at the right edge, aimed across the title it sits beside.
             //
             // Absent rather than disabled on first run, which is the one place this app lets a
-            // control come and go: there is no screen underneath yet, so a Back here would not be
+            // control come and go: there is no screen underneath yet, so a Back here would not be a
-            // a capability being withheld but a promise it could not keep.
+            // capability being withheld but a promise it could not keep.
             if (onBack != null) {
                 GlyphButton(BACK_GLYPH, "Back", onBack)
                 Spacer(Modifier.width(GLYPH_BUTTON_MARGIN))
@@ -106,14 +105,11 @@ fun SettingsScreen(
 
         OutlinedButton(
             onClick = {
-                // Hold the camera permission before the scanner starts.
+                // Hold the camera permission before the scanner starts. Letting its activity ask on
-                // Letting its activity ask on our behalf is what the
+                // our behalf is what the library does by default, and it opens the camera without
-                // library does by default, and it opens the camera without
+                // waiting for the answer: the first-ever scan comes up as a live preview with
-                // waiting for the answer: the first-ever scan comes up as
+                // "Sorry, the Android camera encountered a problem" over it, and works on the
-                // a live preview with "Sorry, the Android camera
+                // second try.
-                // encountered a problem" over it, and works on the second
-                // try. Nothing is wrong with the camera, so nothing should
-                // say there is.
                 if (
                     context.checkSelfPermission(Manifest.permission.CAMERA) ==
                         PackageManager.PERMISSION_GRANTED
@@ -187,11 +183,10 @@ fun SettingsScreen(
  * just been granted.
  *
  * MIXED_SCAN is the load-bearing part: ZXing otherwise looks only for a dark code on a light
- * ground, and ai-server's QR is block characters in the terminal's foreground colour, so on a
+ * ground, and ai-server's QR is block characters in the terminal's foreground colour, so on a dark-
- * dark-themed terminal it comes out as a photographic negative the scanner silently never matches.
+ * themed terminal it comes out as a photographic negative the scanner silently never matches. The
- * Which way round it renders is the terminal's business, not something this app should depend on.
+ * mixed decoder alternates normal and inverted frames, costing half the frame rate at each
- * The mixed decoder alternates normal and inverted frames, costing half the frame rate at each
+ * polarity.
- * polarity and nothing else.
  */
 private fun enrollmentScanOptions(): ScanOptions =
     ScanOptions()

app/androidApp/src/main/kotlin/com/example/aiapp/SetupsScreen.kt

@@ -58,8 +58,8 @@ fun SetupsScreen(settings: ServerSettings, reloadToken: Int) {
     LaunchedEffect(reloadToken) { reload() }
 
     Column(Modifier.fillMaxSize().padding(16.dp)) {
-        // The heading and Back are the tab row's now; adding a machine is this tab's own work
+        // The heading and Back are the tab row's now; adding a machine is this tab's own work and
-        // and stays with the list it adds to.
+        // stays with the list it adds to.
         Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
             TextButton(onClick = { adding = true }) { Text("Add machine") }
         }
@@ -200,9 +200,8 @@ private fun SetupCard(
         Column(Modifier.padding(12.dp)) {
             Text(setup.name, style = MaterialTheme.typography.titleSmall)
             Text(
-                // Not "this machine": the seeded setup is *called* that,
+                // Not "this machine": the seeded setup is *called* that, and the card read "this
-                // and the card read "this machine / this machine". The
+                // machine / this machine".
-                // line has to say something the name cannot also be.
                 setup.address ?: "runs where the backend does",
                 style = MaterialTheme.typography.bodySmall,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
@@ -275,9 +274,8 @@ private fun AddSetupDialog(
                 OutlinedTextField(
                     value = address,
                     onValueChange = { address = it },
-                    // Just the shape. What a blank one means is said once, in the text above
+                    // Just the shape. What a blank one means is said once, in the text above this
-                    // this form -- repeating it here wrapped the label onto a second line and
+                    // form -- repeating it here wrapped the label onto a second line.
-                    // made this field taller than the two beside it for no information.
                     label = { Text("user@host[:port]") },
                     singleLine = true,
                 )
@@ -288,8 +286,7 @@ private fun AddSetupDialog(
                     singleLine = true,
                 )
                 // Where a file attached from the phone lands on that machine. Blank means the
-                // session's own directory, which is what most people want and what needs no
+                // session's own directory, which is what most people want.
-                // path typed on a phone.
                 OutlinedTextField(
                     value = attachmentsDir,
                     onValueChange = { attachmentsDir = it },
@@ -309,9 +306,8 @@ private fun AddSetupDialog(
         },
         dismissButton = {
             Row {
-                // Tried before saving, so a wrong address or an
+                // Tried before saving, so a wrong address or an unauthorised key is caught while
-                // unauthorised key is caught while this form is still on
+                // this form is still on screen rather than at the first spawn.
-                // screen rather than at the first spawn.
                 TextButton(
                     enabled = !testing,
                     onClick = {
@@ -377,14 +373,13 @@ private fun RenameDialog(setup: Setup, onDismiss: () -> Unit, onRename: (String)
 /**
  * Splits `user@host:port` into its two halves, with the port left null when none was typed.
  *
- * One field rather than two because that is how an address is written and read everywhere else --
+ * One field rather than two because that is how an address is written and read everywhere else, and
- * and because a port that is almost always 22 does not deserve a box of its own on a phone
+ * because a port that is almost always 22 does not deserve a box of its own on a phone keyboard.
- * keyboard. Null rather than 22: the backend already decides the default, and writing 22 here would
+ * Null rather than 22: the backend already decides the default.
- * put a second answer to that question in a second place.
  *
  * A colon only means "port" when it can. A bracketed IPv6 literal is unwrapped as ssh writes it,
- * `[::1]:22`; a bare `::1` keeps every colon, because an address with several is an address, not an
+ * `[::1]:22`; a bare `::1` keeps every colon. So the rule is: brackets, or exactly one colon
- * address and a port. So the rule is: brackets, or exactly one colon followed by digits.
+ * followed by digits.
  */
 private fun splitHostAndPort(typed: String): Pair<String, Int?> {
     if (typed.startsWith("[")) {

app/androidApp/src/main/kotlin/com/example/aiapp/Share.kt

@@ -9,7 +9,7 @@ import androidx.core.content.IntentCompat
  *
  * Held as the URIs rather than uploaded on arrival, because an upload belongs to a session and the
  * share arrives before anyone has said which. [serial] makes two shares of the same thing two
- * requests, for the reason [SessionOpenRequest] carries one: equal values would not recompose.
+ * requests, for the reason [SessionOpenRequest] carries one.
  */
 data class ShareRequest(val uris: List<Uri>, val text: String?, val serial: Int)
 

app/androidApp/src/main/kotlin/com/example/aiapp/Sizes.kt

@@ -4,15 +4,12 @@ package com.example.aiapp
  * A byte count at the coarsest unit that still says something, so rows stay comparable.
  *
  * Null at zero and below, because the screens that ask disagree about what nothing means and only
- * the caller knows: a transcript of no bytes is a measurement that has not happened, and is left
+ * the caller knows: a transcript of no bytes is a measurement that has not happened; a file of no
- * off the row; a file of no bytes is a file with nothing in it, and the explorer says `0 B` rather
+ * bytes is a file with nothing in it, and the explorer says `0 B`; a session with no cached
- * than leaving a gap the reader would have to interpret; a session with no cached transcript says
+ * transcript says "nothing cached", because a figure of none would read as a measurement.
- * "nothing cached", because a figure of none would read as a measurement.
  *
  * Its own file rather than the import screen's, where it started: three screens now say a size, and
  * a second copy of these thresholds is how one list comes to call 4 kB what the other calls 4096 B.
- * `ModelsScreen`'s `gigabytes` is deliberately not folded in -- it writes a download's size to two
- * decimal places, which is a different question about a much larger number.
  */
 fun humanSize(bytes: Long): String? =
     when {

app/androidApp/src/main/kotlin/com/example/aiapp/SpawnScreen.kt

@@ -37,7 +37,7 @@ import kotlinx.coroutines.withContext
  * The spawn screen: what to run, where to run it, and the per-kind fields.
  *
  * Providers and hosts both come from the server, so adding either to its config.ron shows up here
- * with no app rebuild -- and because they are independent, any provider can be sent to any host.
+ * with no app rebuild.
  */
 @Composable
 fun SpawnScreen(
@@ -46,33 +46,27 @@ fun SpawnScreen(
     onBack: () -> Unit,
 ) {
     val scope = rememberCoroutineScope()
-    // What the form is made of, and whether we have it yet. A failure here
+    // What the form is made of, and whether we have it yet. A failure here is not the same as a
-    // is not the same as a server with nothing to offer, so it must not
+    // server with nothing to offer, so it must not reach the pickers as empty lists.
-    // reach the pickers as empty lists -- see LoadState.
     var options by remember { mutableStateOf<LoadState<List<Setup>>>(LoadState.Loading) }
 
-    // Setup first, then one of its providers. Choosing a setup can
+    // Setup first, then one of its providers. Choosing a setup can invalidate the provider, so the
-    // invalidate the provider, so the provider is stored by name and
+    // provider is stored by name and resolved against the current setup rather than held as an
-    // resolved against the current setup rather than held as an object
+    // object that could outlive the list it came from.
-    // that could outlive the list it came from.
     var setupName by remember { mutableStateOf<String?>(null) }
     var providerName by remember { mutableStateOf<String?>(null) }
     var title by remember { mutableStateOf("") }
     var model by remember { mutableStateOf("") }
     var cwd by remember { mutableStateOf("") }
-    // "auto" rather than "manual": on a phone every ask is a round trip to
+    // "auto" rather than "manual": on a phone every ask is a round trip to a question card, and
-    // a question card, and answering "allow Bash?" dozens of times per task
+    // answering "allow Bash?" dozens of times per task is what this app exists to avoid.
-    // is what this app exists to avoid. Manual stays one tap away for a
-    // session that warrants it.
     var permissionMode by remember { mutableStateOf("auto") }
     var busy by remember { mutableStateOf(false) }
-    // Only the spawn's own failure. The fetch's lives in `options`: this
+    // Only the spawn's own failure. The fetch's lives in `options`: this one leaves a filled-in
-    // one leaves a filled-in form worth keeping, and that one leaves
+    // form worth keeping, and that one leaves nothing to fill in.
-    // nothing to fill in.
     var spawnError by remember { mutableStateOf<String?>(null) }
-    // Downloaded models, for a llama provider to choose between. Fetched
+    // Downloaded models, for a llama provider to choose between. Kept separate from the setups: a
-    // beside the setups but kept separate: a Claude session needs none, so
+    // Claude session needs none, so failing to list them must not stop the screen rendering.
-    // failing to list them must not stop the screen rendering.
     var models by remember { mutableStateOf<List<LocalModel>>(emptyList()) }
     var modelKey by remember { mutableStateOf<String?>(null) }
     var contextSize by remember { mutableStateOf("") }
@@ -105,10 +99,9 @@ fun SpawnScreen(
         }
         Spacer(Modifier.height(16.dp))
 
-        // Nothing below is fillable until the options are here, and a
+        // Nothing below is fillable until the options are here, and a failure to fetch them leaves
-        // failure to fetch them leaves no form worth showing -- so this
+        // no form worth showing -- so this reports and stops, rather than offering empty pickers
-        // reports and stops, rather than offering empty pickers under an
+        // under an error message.
-        // error message.
         val setups =
             when (val state = options) {
                 is LoadState.Loading -> {
@@ -123,10 +116,9 @@ fun SpawnScreen(
             }
         val setup = setups.firstOrNull { it.name == setupName }
         val current = setup?.providers?.firstOrNull { it.name == providerName }
-        // Only the Claude CLI has models, a working directory and
+        // Only the Claude CLI has models, a working directory and permission modes; keying the
-        // permission modes; keying the extra fields on the kind rather
+        // extra fields on the kind rather than the provider name keeps a second Claude provider
-        // than the provider name keeps a second Claude provider from
+        // from needing anything here.
-        // needing anything here.
         val isClaude = current?.kind == "claude_cli"
         val isLlama = current?.kind == "llama_cpp"
 
@@ -137,9 +129,9 @@ fun SpawnScreen(
             selected = setupName,
             onSelect = { name ->
                 setupName = name
-                // The provider list changes with the machine, so a name
+                // The provider list changes with the machine, so a name carried over from the
-                // carried over from the previous one would be a selection
+                // previous one would be a selection that isn't in the picker. Take that machine's
-                // that isn't in the picker. Take that machine's first.
+                // first.
                 providerName =
                     setups.firstOrNull { it.name == name }?.providers?.firstOrNull()?.name
             },
@@ -150,13 +142,13 @@ fun SpawnScreen(
                 style = MaterialTheme.typography.bodySmall,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )
-            // The address belongs to the setup above it, not to the
+            // The address belongs to the setup above it, not to the provider label below; without
-            // provider label below; without this they read as one block.
+            // this they read as one block.
             Spacer(Modifier.height(8.dp))
         }
 
-        // Only what this machine actually has. A setup with none says so
+        // Only what this machine actually has. A setup with none says so rather than showing an
-        // rather than showing an empty row that reads as a failure.
+        // empty row that reads as a failure.
         if (setup != null && setup.providers.isEmpty()) {
             Text(
                 "\"${setup.name}\" has no providers configured.",
@@ -183,10 +175,9 @@ fun SpawnScreen(
         )
 
         if (isLlama) {
-            // A llama session names one of the models this backend has
+            // A llama session names one of the models this backend has downloaded, so the choice is
-            // downloaded, so the choice is that list rather than free
+            // that list rather than free text -- a name that is not on disk is a session that
-            // text -- there is nothing sensible to type here, and a name
+            // cannot start.
-            // that is not on disk is a session that cannot start.
             if (models.isEmpty()) {
                 Text(
                     "No models downloaded yet. Get one from the Models screen first.",
@@ -196,9 +187,8 @@ fun SpawnScreen(
             } else {
                 ChipGroup(
                     label = "Model",
-                    // The file, not the whole key: the repository is the
+                    // The file, not the whole key: the repository is the same for every
-                    // same for every quantisation of a model, so the file
+                    // quantisation of a model, so the file name is what tells two of them apart.
-                    // name is what tells two of them apart.
                     options = models.map { it.file },
                     selected = models.firstOrNull { it.key == modelKey }?.file,
                     onSelect = { file -> modelKey = models.first { it.file == file }.key },
@@ -280,13 +270,9 @@ fun SpawnScreen(
                             withContext(Dispatchers.IO) {
                                 spawnSession(
                                     settings,
-                                    // The id, not the label: labels are
+                                    // The id, not the label: labels are editable and the server
-                                    // editable and the server resolves by
+                                    // resolves by id. Non-null here, since `chosen` came from
-                                    // id.
+                                    // `setup`'s own provider list.
-                                    // Non-null here: `chosen` came from
-                                    // `setup`'s own provider list, so
-                                    // reaching this point proves there was
-                                    // a setup to take it from.
                                     setup = setup.id,
                                     provider = chosen.name,
                                     title = title.trim(),
@@ -294,9 +280,8 @@ fun SpawnScreen(
                                         if (isLlama) modelKey else model.trim().takeIf { isClaude },
                                     cwd = cwd.trim().takeIf { isClaude },
                                     permissionMode = permissionMode.takeIf { isClaude },
-                                    // Sent only when set, so blank means
+                                    // Sent only when set, so blank means "whatever llama.cpp does
-                                    // "whatever llama.cpp does by default"
+                                    // by default" rather than a zero.
-                                    // rather than a zero.
                                     params =
                                         buildMap {
                                             if (isLlama) {

app/androidApp/src/main/kotlin/com/example/aiapp/Sse.kt

@@ -17,14 +17,13 @@ const val RECONNECT_DELAY_MS = 1500L
  * One server-sent-events connection, framed.
  *
  * The framing is the part worth having once: `data:` and `event:` lines accumulate until a blank
- * line ends the frame, comments (keep-alives) start with `:`, and a frame is either named with no
+ * line ends the frame, comments start with `:`, and a frame is either named with no payload or a
- * payload or a payload with no name. Two screens follow two different streams — a session's
+ * payload with no name. Two screens follow two different streams and neither should re-derive that.
- * transcript and what a machine's import list is doing — and neither should be re-deriving that.
  *
  * Blocking: [run] occupies its thread until the stream ends. [close], from any thread, is the
- * cancellation path — it disconnects the socket, which unblocks the read, and [run] then returns
+ * cancellation path -- it disconnects the socket, which unblocks the read, and [run] then returns
- * rather than throwing, so a deliberate close is not reported as a connection error. Reconnecting
+ * rather than throwing. Reconnecting belongs to the caller, which is the only one that knows where
- * belongs to the caller, which is the only one that knows where to resume from.
+ * to resume from.
  */
 class Sse(private val settings: ServerSettings) {
     @Volatile private var connection: HttpURLConnection? = null
@@ -38,19 +37,16 @@ class Sse(private val settings: ServerSettings) {
     /**
      * Follows the stream at [path], handing each frame to [onFrame] as its name (null for an
      * ordinary data frame) and its payload. The path is given here rather than at construction
-     * because a caller that reconnects usually resumes from somewhere new -- a cursor it has
+     * because a caller that reconnects usually resumes from somewhere new.
-     * advanced past -- and that lives in the query string.
      *
      * [onOpen] fires once the server has accepted the connection. That is the measured moment the
      * stream is live, and the only honest thing to clear a previous failure on: clearing on the
-     * first *event* instead left an idle stream displaying a connection error it had already
+     * first *event* instead left an idle stream displaying an error it had already recovered from.
-     * recovered from, indefinitely.
      */
     fun run(path: String, onOpen: () -> Unit, onFrame: (name: String?, data: String) -> Unit) {
         // Opening is inside the try, not before it. Everything this method can fail at owes the
-        // caller the same kind of failure -- both callers retry an [ApiException] and let anything
+        // caller the same kind of failure, and a connection that could not even be constructed used
-        // else reach the top of the app -- and a connection that could not even be constructed
+        // to escape as a raw `IOException` from a line no `catch` covered.
-        // used to escape as a raw `IOException` from a line no `catch` covered.
         var connection: HttpURLConnection? = null
         try {
             connection =

app/androidApp/src/main/kotlin/com/example/aiapp/Theme.kt

@@ -44,16 +44,14 @@ private object Mocha {
  *
  * Copied from dev-updater rather than shared, which is a deliberate line: wg-app-link is the *link*
  * -- the tunnel, the pinned CA, enrollment -- and a palette is not that. The two apps looking alike
- * is a preference, not a contract, and the moment one wants a different accent the shared version
+ * is a preference, not a contract.
- * becomes a thing to fight rather than a thing to use.
  *
  * The mapping that matters is the surface ladder. Mocha names its darks in order -- Crust, Mantle,
- * Base, Surface 0, Surface 1 -- and Material asks for the same thing under different names, so the
+ * Base, Surface 0, Surface 1 -- so the page is Base, a component's outlined card stays Base beside
- * page is Base, a component's outlined card stays Base beside it, and a project's card is Surface
+ * it, and a project's card is Surface 0: one visible step up, which is the whole of what the
- * 0: one visible step up, which is the whole of what the nesting has to say.
+ * nesting has to say.
  *
- * Accents on this palette are light, so anything filled with one takes Crust for its text rather
+ * Accents on this palette are light, so anything filled with one takes Crust for its text.
- * than the near-white the roles default to.
  */
 val AiAppColors =
     darkColorScheme(
@@ -94,10 +92,8 @@ val AiAppColors =
  * What a session is doing, said in colour.
  *
  * Here rather than beside each screen that shows a status. These were separate literals in two
- * other files -- an amber, a green and a red picked off Material's defaults -- so the same state
+ * other files, so the same state was a slightly different colour depending which screen you looked
- * was a slightly different colour depending which screen you looked at, and none of them belonged
+ * at. A colour that carries meaning is part of the scheme, not a value typed where it was needed.
- * to this palette at all. A colour that carries meaning is part of the scheme, not a value typed
- * where it happened to be needed.
  */
 val runningColor: Color
     @Composable get() = Mocha.Green
@@ -107,7 +103,7 @@ val runningColor: Color
  *
  * The scheme's error colour, and deliberately not "the same red as a destructive button" even
  * though it is the same red. They are the same red for different reasons, and a state is not an
- * action -- nothing here is a button.
+ * action.
  */
 val failedColor: Color
     @Composable get() = MaterialTheme.colorScheme.error
@@ -116,10 +112,9 @@ val failedColor: Color
  * About the session rather than about the task: a command, and the compaction one of them starts.
  *
  * Its own colour because it is its own kind of work. Everything else a session does is progress
- * through what was asked of it; this is the session acting on itself -- rewriting what it
+ * through what was asked of it; this is the session acting on itself, and none of it appears in the
- * remembers, taking a new name -- and none of it appears in the transcript as an answer to
+ * transcript as an answer to anything. A reader who has learned that blue means "not stuck, but not
- * anything. A reader who has learned that blue means "not stuck, but not replying to you either"
+ * replying to you either" has learned what distinguishes it from a session that has hung.
- * has learned the thing that distinguishes it from a session that has hung.
  */
 val commandColor: Color
     @Composable get() = Mocha.Blue
@@ -128,10 +123,9 @@ val commandColor: Color
  * A clear: the conversation taken out of what the session is given.
  *
  * Red because of what it does, not because anything went wrong -- somebody asked for this, and a
- * deliberate choice is not a problem to report. It is the same red as [failedColor] and [stopColor]
+ * deliberate choice is not a problem to report. The same red as [failedColor] and [stopColor] for a
- * for a third reason, which is worth naming rather than collapsing: this is neither a fault nor a
+ * third reason: this is neither a fault nor a button, it is the mark left where something was taken
- * button, it is the mark left where something was taken away. The reader never has to tell the
+ * away. No two of the three can appear as the same kind of thing.
- * three apart, because no two of them can appear as the same kind of thing.
  */
 val clearedColor: Color
     @Composable get() = Mocha.Red
@@ -148,9 +142,9 @@ val warningColor: Color
  * The fill of a progress bar that is only reporting how far along something is.
  *
  * Blue because a bar like this reports a quantity rather than a verdict, and the scheme's primary
- * made it the loudest thing on a screen the reader opened to do something else. A download, or a
+ * made it the loudest thing on a screen the reader opened to do something else. A download has no
- * compaction, has no limit to be near: it finishes. Only a bar measuring a *quota* escalates, and
+ * limit to be near: it finishes. Only a bar measuring a *quota* escalates -- that one is
- * that one is [quotaColor].
+ * [quotaColor].
  */
 val progressColor: Color
     @Composable get() = Mocha.Blue
@@ -158,15 +152,13 @@ val progressColor: Color
 /**
  * The fill of a bar measuring how much of a quota is gone: blue, then yellow, then red.
  *
- * One function rather than the same `when` written beside each bar, because the whole point of
+ * One function rather than the same `when` written beside each bar, because the point of colouring
- * colouring by consequence is that the reader learns the step once -- two bars showing the same 80%
+ * by consequence is that the reader learns the step once. It reads as a difference in degree, which
- * in different colours teaches nothing except that the colour cannot be trusted. It reads as a
+ * is all colour can carry: the states that differ in *kind* -- a window nobody could read, a
- * difference in degree, which is all colour can carry: the states that differ in *kind* from this
+ * machine that meters nothing -- are said in words elsewhere.
- * -- a window nobody could read, a machine that meters nothing -- are said in words elsewhere,
- * because a reader has no way to tell those from an ordinary low number by colour alone.
  *
  * [percent] is the API's own 0-100 rather than a fraction, so callers pass what the server sent
- * without each converting it first and one of them getting it wrong by a factor of a hundred.
+ * without one of them getting it wrong by a factor of a hundred.
  */
 @Composable
 fun quotaColor(percent: Double): Color =
@@ -185,13 +177,11 @@ private const val OVER_LIMIT_PERCENT = 90.0
 /**
  * The surface verbatim text sits on: a command, a tool's output, a code block in a reply.
  *
- * The darkest value in the palette rather than a step up from the page, and that is the whole point
+ * The darkest value in the palette rather than a step up from the page, and that is the point --
- * -- everything else on this screen is somebody's prose, and this is what a machine was handed and
+ * everything else on this screen is somebody's prose, and this is what a machine was handed and
  * what it said back, character for character. Crust sits *below* Base, so the same colour reads as
- * one clear step down both on the page, where a reply is drawn, and on a card, where a tool call
+ * one clear step down both on the page and on a card; a tint chosen upwards has to be picked twice
- * is; a tint chosen upwards has to be picked twice and still collides with the card it lands on.
+ * and still collides with the card it lands on.
- * The renderer's default code background was `surfaceVariant`, which is exactly a card's own fill
- * -- so a code block inside a tool call had no background at all.
  *
  * One colour for all three, so "this is verbatim" is learnable once.
  */
@@ -202,11 +192,10 @@ val rawSurface: Color
  * Catppuccin Mocha as the highlighter's palette; see [SyntaxPalette].
  *
  * Here with the rest of the palette rather than beside the code that highlights: the colours a
- * fence is drawn in are the same accents every other coloured thing in the app already uses, and
+ * fence is drawn in are the same accents every other coloured thing already uses.
- * splitting them out would make code the one surface whose palette came from somewhere else.
  *
- * Not a composable, because [highlight] runs off the drawing thread; these colours never vary with
+ * Not a composable, because [highlight] runs off the drawing thread; these never vary with the
- * the theme.
+ * theme.
  */
 fun catppuccinSyntax(): SyntaxPalette =
     SyntaxPalette(
@@ -227,8 +216,7 @@ fun catppuccinSyntax(): SyntaxPalette =
  * already made for every other blue on the screen.
  *
  * Mocha's bright half is the same accents as its normal half -- only the two greys differ -- which
- * is upstream's choice and not an omission here. A program that uses bright red to mean something
+ * is upstream's choice and not an omission here.
- * other than red is relying on a distinction its own terminal may not draw either.
  *
  * The background is [rawSurface] because that is what a tool's output is drawn on, and reverse
  * video needs to know what it is reversing against.
@@ -263,14 +251,12 @@ fun ansiPalette(): AnsiPalette =
  *
  * The default is `primary` at 40% alpha, which is a tint of whatever is behind it -- and this app
  * draws text on surfaces two full steps apart. Over a reply, on Base, that reads clearly. Over a
- * code block or a tool's output, on Crust, the same 40% composites to a barely-there smudge, so
+ * code block, on Crust, the same 40% composites to a barely-there smudge, so selecting a line of
- * selecting a line of code looks like nothing happened even though the selection is there and
+ * code looks like nothing happened even though it copies correctly.
- * copies correctly.
  *
- * Fixed and stronger, because "this is selected" is a meaning rather than decoration: a colour that
+ * Fixed and stronger, because "this is selected" is a meaning rather than decoration. Raised only
- * means something must carry its own contrast instead of borrowing it from the surface it happens
+ * as far as it takes to read on the darkest of them -- past this the fill starts competing with the
- * to land on. Raised only as far as it takes to read on the darkest of them -- past this the fill
+ * syntax colours it sits behind.
- * starts competing with the syntax colours it sits behind, which are the thing being read.
  */
 val AiAppSelectionColors =
     TextSelectionColors(
@@ -288,11 +274,10 @@ val linkColor: Color
  * A list's markers: the bullets and numbers down its left edge.
  *
  * The scheme's secondary accent rather than the text colour, because a marker is structure rather
- * than words: coloured, the items of a list can be counted without reading them, and a nested list
+ * than words: coloured, the items of a list can be counted without reading them. Lavender is not
- * reads as a shape before it reads as text. Lavender is not one of the colours that mean something
+ * one of the colours that mean something here, and it is the same at every depth, since depth is
- * here -- green, red, peach and yellow are states and actions -- and it is the same at every depth,
+ * said by the glyph and the indent -- a colour per depth would make a difference in degree look
- * since depth is said by the glyph and the indent; a colour per depth would make a difference in
+ * like one in kind.
- * degree look like one in kind.
  */
 val listMarkerColor: Color
     @Composable get() = Mocha.Lavender
@@ -305,11 +290,9 @@ val overLimitColor: Color
  * The composer's buttons, coloured by what pressing one does rather than by where it sits.
  *
  * Green makes something happen now, blue makes it happen later, orange takes back what is in
- * flight, red ends the process. The near-collisions with the states above are deliberate and worth
+ * flight, red ends the process. The near-collisions with the states above are deliberate: those are
- * naming rather than collapsing: [runningColor] is green because a session is working,
+ * *states*, and these are *actions*. A reader never has to tell them apart, because nothing here is
- * [failedColor] is red because one fell over, [awaitingColor] is the same orange because a session
+ * a state and nothing there is pressable.
- * is waiting on somebody -- those are *states*, and these are *actions*. A reader never has to tell
- * them apart, because nothing here is a state and nothing there is pressable.
  */
 val sendColor: Color
     @Composable get() = Mocha.Green
@@ -322,9 +305,8 @@ val queueColor: Color
  * Interrupting the running turn: the work stops and the session stays.
  *
  * Orange rather than red because of how much it takes: only what is in flight. The process is still
- * there holding the conversation, and the next message starts a turn as though nothing had
+ * there holding the conversation. Red is spent on [stopColor], which is the same button in the same
- * happened. Red is spent on [stopColor], which is the same button in the same place when what it
+ * place when what it would end is the session's process.
- * would end is the session's process.
  */
 val pauseColor: Color
     @Composable get() = Mocha.Peach
@@ -347,8 +329,7 @@ val startColor: Color
  *
  * The content colour is stated here beside the fill rather than inherited. A semantic colour has to
  * carry its own contrast: these fills are fixed whatever the surface under them does, so the theme
- * will not change to rescue a foreground that stops being readable on one of them. Crust is what
+ * will not change to rescue a foreground that stops being readable on one of them.
- * every accent on this palette takes, which is the same reason `onPrimary` is Crust above.
  */
 @Composable
 fun actionButtonColors(fill: Color): ButtonColors =

app/androidApp/src/main/kotlin/com/example/aiapp/ToolInput.kt

@@ -16,11 +16,10 @@ import org.json.JSONObject
 /**
  * A tool call's input, read rather than dumped.
  *
- * Every tool's input arrives as JSON, and showing it raw makes the reader parse `{"command":"…",
+ * Every tool's input arrives as JSON, and showing it raw makes the reader parse
- * "timeout":120000}` themselves to find the one line they care about. So the fields that carry the
+ * `{"command":"…","timeout":120000}` themselves to find the one line they care about. So the fields
- * meaning are pulled out -- the command a shell will run, what it is for, how long it may take --
+ * that carry the meaning are pulled out, and anything left over is still shown, because dropping a
- * and anything left over is still shown, because dropping a field would be claiming the tool has no
+ * field would be claiming the tool has no other input when it might.
- * other input when it might.
  */
 data class ToolInput(
     /** The thing that will actually be run or read, if this tool has one. */
@@ -30,8 +29,8 @@ data class ToolInput(
     /** The tool's own one-line summary, when it wrote one. */
     val description: String?,
     /**
-     * How long the call may take, in the largest units it fits ([formatMillis]). Shown apart
+     * How long the call may take, in the largest units it fits. Shown apart because it is a limit
-     * because it is a limit on the call rather than part of what the call does.
+     * on the call rather than part of what the call does.
      */
     val timeout: String?,
     /** Everything else, as `name: value` lines. Never dropped. */
@@ -47,7 +46,7 @@ data class ToolInput(
  *
  * A table rather than a chain of `if`s: adding a tool is a row, and the shape stops any of them
  * from being the special case that gets its own code path. Unknown tools fall through to "no
- * subject, everything is rest", which is what the card always did.
+ * subject, everything is rest".
  */
 private val SUBJECTS: Map<String, Pair<String, Language?>> =
     mapOf(
@@ -68,8 +67,8 @@ fun parseToolInput(tool: String, input: String): ToolInput {
         try {
             JSONObject(input)
         } catch (_: org.json.JSONException) {
-            // Not an object: older transcripts and some tools send a bare
+            // Not an object: older transcripts and some tools send a bare string. It is still the
-            // string. It is still the input, so it is still shown.
+            // input, so it is still shown.
             return ToolInput(
                 null,
                 null,
@@ -100,9 +99,9 @@ fun parseToolInput(tool: String, input: String): ToolInput {
 /**
  * A tool call's input: its subject highlighted, then whatever else it carried.
  *
- * On the dark surface every verbatim thing in the app sits on -- see [RawBlock]. Drawn as nothing
+ * On the dark surface every verbatim thing in the app sits on. Drawn as nothing at all when the
- * at all when the call carried neither, rather than as an empty block: a tinted rectangle with
+ * call carried neither, rather than as an empty block: a tinted rectangle with nothing in it is a
- * nothing in it is a rendering fault, and it is the shape a tool with no input actually has.
+ * rendering fault.
  *
  * The description is *not* here. It is the tool's own prose about what it is doing, so it belongs
  * with the reader's text rather than inside the machine's; [ToolCard] draws it above this.
@@ -113,11 +112,11 @@ fun ToolInputView(tool: String, input: String, modifier: Modifier = Modifier) {
     if (parsed.subject == null && parsed.rest.isEmpty()) return
     RawBlock(modifier) {
         parsed.subject?.let { subject ->
-            // Not wrapped: a wrapped command hides where its arguments end,
+            // Not wrapped: a wrapped command hides where its arguments end, and the long one is the
-            // and the long one is the one being read closely.
+            // one being read closely.
             Text(
-                // Not cached: a tool's subject is one command line, which lexes in microseconds
+                // Not cached: a tool's subject is one command line, which lexes in microseconds --
-                // -- the cache exists for a fence with two hundred lines in it.
+                // the cache exists for a fence with two hundred lines in it.
                 remember(subject, parsed.language) { highlight(subject, parsed.language) },
                 style = MaterialTheme.typography.bodySmall,
                 fontFamily = FontFamily.Monospace,

app/androidApp/src/main/kotlin/com/example/aiapp/ToolRows.kt

@@ -42,14 +42,11 @@ import androidx.compose.ui.unit.dp
  * the transcript's own order is what paging and the event stream depend on, and one screen's idea
  * of "these belong together" must not reach back into it.
  *
- * Immutable, and said so, because Compose cannot tell.
+ * Immutable, and said so, because Compose cannot tell: a row is rebuilt from the transcript rather
- *
+ * than edited, and two rows describing the same events are equal. Compose infers stability from a
- * A row is a value: it is rebuilt from the transcript rather than edited, and two rows describing
+ * class's fields, and a `List` field -- which several of these carry -- makes it assume the worst,
- * the same events are equal. Compose infers stability from a class's fields, and a `List` field --
+ * so a page of history landing recomposed all 148 loaded rows including the markdown inside them,
- * which several of these carry -- makes it assume the worst, so every composable taking one
+ * measured as 701 compositions for 148 rows in one scroll.
- * recomposed whenever anything above it did. A page of history landing recomposed all 148 loaded
- * rows including the markdown inside them, measured as 701 compositions for 148 rows in one scroll,
- * and that is what a page landing costs on top of the fetch itself.
  *
  * The promise this makes is real and has to stay true: nothing here is mutated after it is built.
  */
@@ -59,16 +56,12 @@ sealed class TranscriptRow {
      * This row's identity in the list, which must survive everything that can happen to the row.
      *
      * The list is keyed by this so that inserting a new message at one end, or a page of history at
-     * the other, moves the rows and not the reader. That makes it the load-bearing value on this
+     * the other, moves the rows and not the reader. When a key changes, the list loses its anchor
-     * screen: when a key changes, the list loses its anchor and the transcript steps under whoever
+     * and the transcript steps under whoever is reading it.
-     * is reading it.
      *
      * A tool row therefore keys on [TranscriptItem.ToolRun.runId] rather than on a sequence number,
-     * and it is the *same* value whether the run is drawn as one card or as a group. A lone call
+     * and it is the *same* value whether the run is drawn as one card or as a group. Which value
-     * that gains a neighbour becomes a group without changing identity, which is the case a
+     * that is belongs to the item ([TranscriptItem.key]), not to a `when` here.
-     * seq-based key got wrong: the row the reader was looking at was replaced rather than updated.
-     * Which value that is belongs to the item ([TranscriptItem.key]), not to a `when` here: a row
-     * is one item and the item is what knows what it is called.
      */
     abstract val key: Any
 
@@ -76,12 +69,9 @@ sealed class TranscriptRow {
      * Where this row starts in the transcript: the sequence number of the oldest event behind it.
      *
      * Separate from [key], and deliberately so. [key] is the list's identity and is a display
-     * decision -- a tool row is named after its run, and a run takes its name from whichever call
+     * decision; a seq is the server's own numbering, assigned once and meaning the same thing to
-     * was first when it was folded, which changes as pages arrive. A seq is the server's own
+     * every device. So anything that has to point at a place in the conversation and still find it
-     * numbering: it is assigned once, never moves, and means the same thing to every device. So
+     * later -- a saved scroll position -- points with this.
-     * anything that has to point at a place in the conversation and still find it later -- a saved
-     * scroll position is the one -- points with this, and anything that has to identify a row
-     * within one composition uses [key].
      */
     abstract val startSeq: Long
 
@@ -133,8 +123,7 @@ private fun groupRuns(items: List<TranscriptItem>): List<TranscriptRow> {
         // Grouped by the run each call says it belongs to, not by adjacency worked out here.
         // Adjacency is the same answer most of the time and a worse one at the edges: a call
         // arriving next to an existing run, or a page of history arriving in front of one, both
-        // change which call is *first*, and a group named after its first member is a different
+        // change which call is *first*.
-        // group every time that happens.
         if (item is TranscriptItem.ToolRun && (run.isEmpty() || run.first().runId == item.runId)) {
             run += item
         } else {
@@ -152,18 +141,14 @@ private fun groupRuns(items: List<TranscriptItem>): List<TranscriptRow> {
  * What says the calls belong together is the surface behind them, which is the one cue rather than
  * two half-cues -- rounded to the same corner every other card in the app has, so a group reads as
  * one object rather than as a square patch behind round things. The calls sit on it inset by
- * [GROUP_INSET], which is the container's own padding rather than an indent: they are the same rows
+ * [GROUP_INSET], which is the container's own padding rather than an indent.
- * they would be on their own, and a rounded corner drawn hard against a rounded corner reads as a
- * notch.
  *
  * Inside, the calls are a connected stack. Facing corners are square and the outer ones are not, so
- * the run reads as one thing broken into its parts; [GROUP_GAP] keeps the parts legible without
+ * the run reads as one thing broken into its parts; see [connectedShape].
- * separating them. See [connectedShape].
  *
  * It closes from either end. A long group's header scrolls off while its last call is still on
- * screen, and the reader who wants it shut is looking at the bottom, not hunting for the top. The
+ * screen, and the reader who wants it shut is looking at the bottom. The bar at the foot is the
- * bar at the foot is the same height as the heading at the top, so the surface the calls sit on is
+ * same height as the heading at the top.
- * as thick below them as above.
  */
 @Composable
 fun ToolGroup(
@@ -171,8 +156,7 @@ fun ToolGroup(
     expanded: Boolean,
     /**
      * Where it was pressed is the row's business rather than the control's -- a group has a control
-     * at each end, and only the row knows where its own ends are, so the row records the touch
+     * at each end, and only the row knows where its own ends are.
-     * itself and this just says that one happened.
      */
     onToggle: () -> Unit,
     isToolExpanded: (String) -> Boolean,
@@ -222,8 +206,8 @@ fun ToolGroup(
                 )
             }
         }
-        // Shutting it from here anchors the other end: the reader is at the bottom of a long
+        // Shutting it from here anchors the other end: the reader is at the bottom of a long group,
-        // group, and what they are looking at is what follows it.
+        // and what they are looking at is what follows it.
         CollapseBar(barHeight, onToggle)
     }
 }
@@ -232,8 +216,8 @@ fun ToolGroup(
  * The height of a group's heading, and so of the bar at its foot.
  *
  * Derived from the type the heading is set in rather than written down, because the two have to
- * match and a pair of numbers chosen to look equal stops being equal the moment either the style or
+ * match and a pair of numbers chosen to look equal stops being equal the moment the density
- * the density changes. Taking the line height also means the heading cannot be clipped by it.
+ * changes.
  */
 @Composable
 private fun groupBarHeight(): Dp {
@@ -242,10 +226,9 @@ private fun groupBarHeight(): Dp {
 }
 
 /**
- * The bottom half of a group's toggle: an arrow back up to its heading.
+ * The bottom half of a group's toggle: an arrow back up to its heading. Given the heading's height
- *
+ * rather than padded to something that looks close, so the surface the calls sit on is the same
- * Given the heading's height rather than padded to something that looks close, so the surface the
+ * thickness at both ends.
- * calls sit on is the same thickness at both ends. See [groupBarHeight].
  */
 @Composable
 private fun CollapseBar(height: Dp, onToggle: () -> Unit) {
@@ -266,8 +249,7 @@ private fun CollapseBar(height: Dp, onToggle: () -> Unit) {
  * does not.
  *
  * Written once and given an index rather than branched at each end, because a stack has three cases
- * that are one rule -- and the middle one is the case a hand-written first/last pair gets wrong
+ * that are one rule -- and the middle one is what a hand-written first/last pair gets wrong.
- * when a run turns out to have three calls in it.
  */
 @Composable
 private fun connectedShape(index: Int, count: Int): CornerBasedShape {
@@ -294,12 +276,10 @@ private val GROUP_GAP = 2.dp
  * One tool call.
  *
  * Closed, it is a single line: the tool's name and what the call is for. The command itself is not
- * on it, because a wrapped command turns one row into four and a run of them into a wall -- and the
+ * on it, because a wrapped command turns one row into four and a run of them into a wall.
- * name plus the intent is what somebody scanning the transcript is reading for.
  *
  * Open, it shows the command, whatever else the input carried, and the output. The timeout sits at
- * the top right: it is a limit on the call rather than part of what the call does, and it is worth
+ * the top right: it is a limit on the call rather than part of what the call does.
- * seeing beside the command it constrains rather than buried in the fields below it.
  *
  * A call waiting on permission is shown open whatever the reader last chose, since the command is
  * the thing being decided and a row saying only "Bash" cannot be decided on.
@@ -342,10 +322,9 @@ fun ToolCard(
                         )
                     } ?: Spacer(Modifier.weight(1f))
                 }
-                // A spinner says the machine is working. While this call is waiting on an
+                // A spinner says the machine is working. While this call is waiting on an answer
-                // answer the machine is doing nothing at all -- the turn is stopped on the
+                // the machine is doing nothing at all -- the turn is stopped on the person reading
-                // person reading it -- so it says whose move it is instead, in the colour this
+                // it -- so it says whose move it is instead.
-                // app uses everywhere for that.
                 if (deciding) {
                     Spacer(Modifier.width(8.dp))
                     Text(
@@ -370,9 +349,9 @@ fun ToolCard(
                         modifier = Modifier.padding(top = 4.dp),
                     )
                 }
-                // Everything AskUserQuestion carries is the questions, and those are drawn
+                // Everything AskUserQuestion carries is the questions, and those are drawn below as
-                // below as something answerable; dumping the same JSON above them would be the
+                // something answerable; dumping the same JSON above them would be the decision
-                // decision stated twice, once unreadably.
+                // stated twice, once unreadably.
                 if (tool.tool != ASK_USER_QUESTION) {
                     ToolInputView(tool.tool, tool.input, Modifier.padding(top = 4.dp))
                 }
@@ -381,14 +360,12 @@ fun ToolCard(
                     Text("Output", style = MaterialTheme.typography.labelSmall)
                     // What the tool printed, on the surface everything verbatim gets and in the
                     // face it was written for: this is column-aligned far more often than it is
-                    // prose -- a directory listing, a diff, a table of numbers -- and a
+                    // prose, and a proportional font silently destroys the alignment that carried
-                    // proportional font silently destroys the alignment that carried the meaning.
+                    // the meaning.
                     //
-                    // Its terminal styling applied and the rest of the escapes taken out, since
+                    // Its terminal styling applied and the rest of the escapes taken out: colour is
-                    // what a shell prints is written for a terminal: colour is often the whole of
+                    // often the whole of what a diff or a test run is saying. Remembered against
-                    // what a diff or a test run is saying, and the sequences that carry it are
+                    // the text, so a card that is open through a scroll parses once.
-                    // unreadable drawn verbatim. Remembered against the text, so a card that is
-                    // open through a scroll parses once. See [ansiStyled].
                     val palette = remember { ansiPalette() }
                     val styled = remember(tool.output, palette) { ansiStyled(tool.output, palette) }
                     RawBlock(Modifier.padding(top = 2.dp)) {
@@ -400,10 +377,8 @@ fun ToolCard(
                     }
                 }
             }
-            // Shown open or closed. A call that produced a picture is one
+            // Shown open or closed. A call that produced a picture is one whose result *is* the
-            // whose result *is* the picture, and a row that hides it says
+            // picture, and a row that hides it says less than the one line it replaced.
-            // less than the one line it replaced -- unlike a command, which
-            // is what the closed line already summarises.
             tool.images.forEach { ref -> image(ref) }
             if (tool.asks.isNotEmpty()) {
                 if (tool.tool == ASK_USER_QUESTION) {
@@ -428,11 +403,10 @@ private fun PermissionAsk(
     onAnswer: (List<QuestionAnswer>, onSettled: () -> Unit) -> Unit,
 ) {
     // What was pressed, before the answer has been round-tripped. Two bare words with no submit
-    // step -- unlike a question card, where the answer is several choices and worth reviewing --
+    // step -- unlike a question card, where the answer is worth reviewing -- so the press has to be
-    // so the press has to be its own acknowledgement or the row sits unchanged for a round trip
+    // its own acknowledgement or the row sits unchanged for a round trip. Cleared when the request
-    // and reads as having missed the tap. Cleared when the request settles: by then either the
+    // settles: by then either the answer is in `ask.answers`, or it failed and the buttons come
-    // answer is in `ask.answers` and the mark stands on a measurement, or it failed and the
+    // back.
-    // buttons come back rather than leaving a decision marked that nothing recorded.
     var pressed by remember(ask.id) { mutableStateOf<String?>(null) }
     Spacer(Modifier.height(8.dp))
     Text(
@@ -442,8 +416,7 @@ private fun PermissionAsk(
     )
     // Answered or not, the options stay and the one that was taken is marked -- see
     // [AskedQuestion], which is the same rule on the question card. A permission is where it
-    // matters most: "Answered: Deny" alone does not say that Allow was the alternative, and
+    // matters most: "Answered: Deny" alone does not say that Allow was the alternative.
-    // whether a tool was allowed or refused is the thing a reader comes back to this row for.
     val settled = ask.answers.isNotEmpty()
     AnswerOptions(
         ask.options,

app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptCache.kt

@@ -11,30 +11,25 @@ import java.io.RandomAccessFile
  * This phone's copy of the transcripts it has already been sent, so reopening a session does not
  * download it again.
  *
- * What is stored is the server's own JSON for one event per line, in transcript order -- the
+ * What is stored is the server's own JSON for one event per line, in transcript order. Reading the
- * elements of a `/transcript` page and the payload of each SSE frame. Reading the cache means
+ * cache means running the same [parseSeqEvent] the network path runs, so a cached transcript and a
- * running the same [parseSeqEvent] the network path runs, so a cached transcript and a fetched one
+ * fetched one cannot draw differently, and an event type this build does not know keeps every field
- * cannot draw differently, and an event type this build does not know ([SessionEvent.Unknown])
+ * it arrived with for the build that will. Rows are deliberately *not* what is stored: a row is a
- * keeps every field it arrived with, on disk, for the build that will. Rows are deliberately *not*
+ * rendering, and a cache of rows would need throwing away on every update that touched `foldEvent`.
- * what is stored: a row is a rendering of events, its shape changes whenever the fold does, and a
- * cache of rows would need throwing away on every app update that touched `foldEvent`.
  *
  * See TRANSCRIPT_CACHE.md for the design. Four rules run through all of it:
  * 1. what is on screen is what the server's transcript says, in order, with nothing missing -- the
  *    cache is a copy and is never inferred, folded or edited here;
  * 2. a cached line is never ahead of the live cursor, and the cursor never ahead of the cache;
  * 3. the cache is never load-bearing -- missing, evicted, damaged or unwritable all degrade to a
- *    cold open, never to a blank or a wrong screen;
+ *    cold open, never to a blank or a wrong screen; 4. a line already on the phone is not fetched
- * 4. a line already on the phone is not fetched again.
+ *    again.
  *
  * A plain [File] root and no Compose, `Context` or network, so the whole of the file logic runs
- * under the JVM unit tests. It is also why there is no JSON parser in here: what it needs off a
+ * under the JVM unit tests. That is also why there is no JSON parser here: what it needs off a line
- * line is the sequence number and whether the line is a streamed delta, and both are read with a
+ * is the sequence number and whether the line is a streamed delta, both read with a regex. A line
- * regex over text the server wrote. A line it cannot read that way is treated as damage, which
+ * it cannot read that way is treated as damage. [warn] is where failures are said for the same
- * gives the same answer as having no cache at all.
+ * reason.
- *
- * [warn] is where failures are said, for the same reason -- `android.util.Log` is a stub that
- * throws under the JVM tests, and this file has to be exercisable there.
  */
 class TranscriptCache(
     private val root: File,
@@ -44,11 +39,9 @@ class TranscriptCache(
     fun session(id: String): SessionCache = SessionCache(File(root, id), warn)
 
     /**
-     * Deletes every session directory not in [ids], called after a successful list fetch.
+     * Deletes every session directory not in [ids], called after a successful list fetch. The path
-     *
+     * out for a session deleted on another device: nothing here would otherwise hear about it, and
-     * The path out for a session deleted on another device or at the backend: nothing here would
+     * unlike a draft's few bytes what it leaves behind is megabytes.
-     * otherwise ever hear about it, and unlike a draft's few bytes what it leaves behind is
-     * megabytes.
      */
     fun retainOnly(ids: Set<String>) =
         guardIo(Unit, warn) {
@@ -57,11 +50,9 @@ class TranscriptCache(
 
     /**
      * Deletes least-recently-touched session directories, never [keep], until the whole of this
-     * server's cache is under [budget].
+     * server's cache is under [budget]. Least-recently-touched rather than largest: what a reader
-     *
+     * is likely to open again is what they opened last, and evicting the big ones first would empty
-     * Least-recently-touched rather than largest: what a reader is likely to open again is what
+     * the cache for exactly the conversations it exists for.
-     * they opened last, and evicting the big ones first would empty the cache for exactly the
-     * conversations it exists for.
      */
     fun evictToBudget(keep: String, budget: Long = CACHE_BUDGET_BYTES) =
         guardIo(Unit, warn) {
@@ -81,18 +72,16 @@ class TranscriptCache(
 }
 
 /**
- * How much of this phone's cache directory all of one server's transcripts may take.
+ * How much of this phone's cache directory all of one server's transcripts may take. A dozen of the
- *
+ * largest transcripts seen in the dev VM (21 MB for 24,000 events) and a small fraction of a phone.
- * A dozen of the largest transcripts seen in the dev VM (21 MB for 24,000 events) and a small
+ * A number to revisit against real use rather than a measurement of anything.
- * fraction of a phone. A number to revisit against real use rather than a measurement of anything.
  */
 const val CACHE_BUDGET_BYTES: Long = 256L * 1000 * 1000
 
 /**
- * What the newest cached line says, which is what the probe checks against the server.
+ * What the newest cached line says, which is what the probe checks against the server. Both halves
- *
+ * are wanted together: the seq is what the request asks about, and the line is what its answer is
- * Both halves are wanted together and by the same caller: the seq is what the request asks about,
+ * compared with.
- * and the line is what its answer is compared with.
  */
 data class CachedTail(val seq: Long, val line: String)
 
@@ -101,35 +90,31 @@ data class CachedTail(val seq: Long, val line: String)
  *
  * A chunk is a set of lines *and a claim about what they cover*, and the two are not the same
  * thing: a coalesced page joins each run of streamed deltas into one event carrying the seq of the
- * run's oldest delta, so a page whose newest event is seq 1,200 may in fact cover everything up to
+ * run's oldest delta, so a page whose newest event is seq 1,200 may cover everything up to the
- * the 1,650 it was fetched with, and nothing in the lines says so. So coverage is the half-open
+ * 1,650 it was fetched with, and nothing in the lines says so. So coverage is the half-open range
- * range in the file's name:
+ * in the file's name:
  * ```
- *   <first>-<end>.rows.jsonl     a coalesced page; end is the `before` it was fetched with
+ * <first>-<end>.rows.jsonl     a coalesced page; end is the `before` it was fetched with
- *   <first>-<end>.raw.jsonl      an uncoalesced page, or a closed live run
+ * <first>-<end>.raw.jsonl      an uncoalesced page, or a closed live run <first>-open.raw.jsonl the
- *   <first>-open.raw.jsonl       the live run; end is its last line's seq + 1
+ * live run; end is its last line's seq + 1
  * ```
  *
- * Two chunks are adjacent when one's `end` is the other's `first`. Only the contiguous run of
+ * Two chunks are adjacent when one's `end` is the other's `first`. Only the contiguous run ending
- * adjacent chunks ending at the newest chunk -- the **suffix** -- is ever served: chunks behind a
+ * at the newest chunk -- the **suffix** -- is ever served: chunks behind a gap are kept, because
- * gap are kept, because the gap is usually closed by paging back through it, but nothing is served
+ * the gap is usually closed by paging back through it, but nothing is served across one.
- * across one.
  *
  * **The newest chunk is always raw**, which is what makes the stream cursor and the probe well
- * defined -- a raw chunk's last line is a real event at a real seq, and the server never coalesces
+ * defined. It holds by construction (the opening window and every stream frame are raw) and is
- * the newest window. It holds by construction (the opening window and every stream frame are raw)
+ * checked on read: a `.rows` chunk at the newest end can only mean this app died between closing
- * and is checked on read: a `.rows` chunk at the newest end can only mean this app died between
+ * one live run and opening the next, and it discards the session.
- * closing one live run and opening the next, and it discards the session.
  *
  * Nothing here is load-bearing. Every operation that touches the disk answers as though the cache
  * were empty when it cannot, and a write failure disables writing for the rest of this instance's
  * life so that a full disk costs one log line rather than one per delta.
  *
  * Every operation is synchronized, because two of them really do run at once: the stream appends
- * live events from its own IO thread while a reader scrolling back reads pages from another. The
+ * live events from its own IO thread while a reader scrolling back reads pages from another. What
- * lock is uncontended in the ordinary case and what it buys is that the open chunk's name, its end
+ * it buys is that the open chunk's name, its end and its writer are never read half-rotated.
- * and its writer are never read half-rotated -- which would show up as a page silently fetched
- * again, or as a stored chunk overlapping the run it was written beside.
  */
 class SessionCache(
     private val dir: File,
@@ -141,9 +126,8 @@ class SessionCache(
      * The open chunk's writer, its file, and the seq that chunk now ends at.
      *
      * Buffered, and flushed on [flush], because a delta is a hundred bytes and arrives dozens of
-     * times a second while a reply streams -- a syscall each is the thing to avoid. What that costs
+     * times a second while a reply streams. What that costs is the unflushed tail on a crash, which
-     * is the unflushed tail on a crash, which is safe: a shorter cache is a longer catch-up, never
+     * is safe: a shorter cache is a longer catch-up, never a wrong one.
-     * a wrong one.
      */
     private var writer: BufferedWriter? = null
     private var openFile: File? = null
@@ -153,8 +137,7 @@ class SessionCache(
      * The newest line of the suffix, or null when there is none or the newest chunk is not raw.
      *
      * This is the cursor the live stream would resume from, so it is also what has to be shown to
-     * still be the server's own line before anything is resumed from it -- see
+     * still be the server's own line before anything is resumed from it.
-     * `TranscriptSource.probe`.
      */
     @Synchronized
     fun tail(): CachedTail? =
@@ -187,30 +170,26 @@ class SessionCache(
      * The page of lines before [before], oldest first, or null when the cache cannot answer.
      *
      * Null is a miss -- the suffix does not cover the ground immediately below [before] -- and
-     * means the server has to be asked. It is deliberately not an empty list: an empty page is how
+     * means the server has to be asked. Deliberately not an empty list: an empty page is how the
-     * the screen is told it has reached the start of the conversation, and a cache saying that of
+     * screen is told it has reached the start of the conversation, and a cache saying that of
      * history it merely does not hold would stop the transcript scrolling back for good.
      *
      * [before] is anywhere inside the suffix, not only at a chunk boundary. The cursor a warm open
-     * leaves behind is in the middle of the live run -- the screen draws the newest eighty lines of
+     * leaves behind is in the middle of the live run, so a cache that could only answer at a
-     * it -- so a cache that could only answer at a boundary would send the very first backwards
+     * boundary would send the very first backwards page to the server and, since that page would
-     * page to the server and, since that page would overlap the run, keep none of it.
+     * overlap the run, keep none of it.
      *
-     * A short page is fine, and is what a walk that reaches the oldest chunk of the suffix returns:
+     * With [rows] the count is rows rather than lines, mirroring the server's `parse_coalesced`.
-     * the caller already treats a short page as a page.
-     *
-     * With [rows] the count is rows rather than lines, mirroring the server's `parse_coalesced`:
-     * every event that is not a streamed delta is a row, and each maximal run of deltas is one row.
      * The deltas are not joined here -- `foldEvent` does that, and the joined row keeps the seq of
-     * its first delta either way, so anchors and the next `before` land where they do today.
+     * its first delta either way.
      */
     @Synchronized
     fun page(before: Long, limit: Int, rows: Boolean): List<String>? =
         guard(null) {
             val suffix = suffix()
             val newest = suffix.lastOrNull() ?: return@guard null
-            // Above what is held, or at or below where it starts: either way the run the caller
+            // Above what is held, or at or below where it starts: either way the run the caller is
-            // is scrolling into is not continuous with this one, and only the server has it.
+            // scrolling into is not continuous with this one, and only the server has it.
             if (before > newest.end || before <= suffix.first().first) return@guard null
             val taken = ArrayDeque<String>()
             var counted = 0
@@ -220,14 +199,14 @@ class SessionCache(
                 if (!wanting) break
                 if (chunk.first >= before) continue
                 eachLine(chunk) { line ->
-                    // The page is what is *before* the cursor; the rows at or above it are the
+                    // The page is what is *before* the cursor; the rows at or above it are already
-                    // ones already on screen.
+                    // on screen.
                     if (seqOf(line)!! >= before) return@eachLine true
                     if (rows) {
                         val delta = isDelta(line)
-                        // Stop only between rows: a delta continuing the run being gathered is
+                        // Stop only between rows: a delta continuing the run being gathered is part
-                        // part of a row already counted, and breaking on it would drop the half
+                        // of a row already counted, and breaking on it would drop the half of that
-                        // of that row already taken.
+                        // row already taken.
                         if (counted >= limit && !(delta && inRun)) wanting = false
                         else {
                             if (!delta || !inRun) counted++
@@ -248,8 +227,7 @@ class SessionCache(
      * asked with so that it stops where this phone's copy starts. Null when there is no such chunk.
      *
      * Any chunk, not only the suffix's: the whole point is to reach the run behind a gap, so that
-     * the gap is closed with exactly the bytes it is wide and the history behind it is served
+     * the gap is closed with exactly the bytes it is wide.
-     * locally from then on.
      */
     @Synchronized
     fun coveredUpTo(before: Long): Long? =
@@ -260,9 +238,8 @@ class SessionCache(
      *
      * Refused when it overlaps a chunk already here, because there is no clean cut: a coalesced
      * event cannot be split at a seq inside its own delta run. `TranscriptSource` keeps that from
-     * arising by bounding what it fetches, and this is the guard for a page that arrives anyway --
+     * arising by bounding what it fetches, and this is the guard for a page that arrives anyway.
-     * from a server without the `after` parameter, say. Such a page is still drawn; it is only not
+     * Such a page is still drawn; it is only not kept.
-     * kept.
      *
      * The newest chunk is never stored through here: the opening window and every live frame go
      * through [append], which is what keeps the newest chunk raw and open.
@@ -282,18 +259,17 @@ class SessionCache(
      * Appends one live event, which is also how a freshly fetched opening window is stored.
      *
      * A seq equal to the open chunk's end extends it. A larger one is a gap -- which is what a
-     * `reset` looks like from here -- and closes the open chunk under the end it turned out to have
+     * `reset` looks like from here -- and closes the open chunk under the end it turned out to
-     * before starting a new one at [seq]. A smaller one is already covered and is ignored; the SSE
+     * have. A smaller one is already covered and is ignored; the SSE contract is `seq > after`.
-     * contract is `seq > after`, so that is a guard rather than a path.
      */
     @Synchronized
     fun append(line: String, seq: Long) =
         guard(Unit) {
             if (disabled) return@guard
             val writer = writerFor(seq) ?: return@guard
-            // Written as it arrived. A newline inside it would split one event into two
+            // Written as it arrived. A newline inside it would split one event into two unreadable
-            // unreadable halves, but neither source can produce one: SSE framing forbids it, and
+            // halves, but neither source can produce one: SSE framing forbids it, and a page's
-            // a page's elements are re-serialized compactly, which escapes it.
+            // elements are re-serialized compactly, which escapes it.
             writer.write(line)
             writer.write("\n")
             openEnd = seq + 1
@@ -329,9 +305,7 @@ class SessionCache(
 
     /**
      * Every chunk on disk, oldest first. A name this does not recognise is not ours and is ignored.
-     *
+     * Recomputed per operation rather than kept: another operation may have changed the directory.
-     * Recomputed per operation rather than kept: another operation may have changed the directory,
-     * and a hundred names is a directory listing.
      */
     private fun chunks(): List<Chunk> {
         writer?.flush()
@@ -354,9 +328,9 @@ class SessionCache(
      * is the one writing it.
      *
      * An open chunk whose last line cannot be read is this app having died mid-write. That line is
-     * dropped and the file truncated to the last good one before anything is served from it, which
+     * dropped and the file truncated to the last good one, which is the one place damage is
-     * is the one place damage is repaired rather than discarded: the tail of an append-only file is
+     * repaired rather than discarded: the tail of an append-only file is the only place a partial
-     * the only place a partial line can be.
+     * line can be.
      */
     private fun openEndOf(file: File, first: Long): Long {
         if (openFile == file && openEnd > 0) return openEnd
@@ -373,8 +347,7 @@ class SessionCache(
      * The contiguous run of adjacent chunks ending at the newest one, oldest first.
      *
      * A newest chunk that is not raw cannot happen while this code is the only writer, and means
-     * the directory is not to be trusted -- so the session is discarded rather than served across
+     * the directory is not to be trusted -- so the session is discarded.
-     * whatever else is wrong with it.
      */
     private fun suffix(): List<Chunk> {
         val all = chunks()
@@ -393,10 +366,9 @@ class SessionCache(
     /**
      * Each line of [chunk], newest first, until [take] says stop.
      *
-     * Backwards and lazily, because every question this cache is asked is about the newest end --
+     * Backwards and lazily, because every question this cache is asked is about the newest end and
-     * the tail, the opening window, the page before a cursor -- and a live run grows to the size of
+     * a live run grows to the size of the conversation. Reading the file whole to answer with
-     * the conversation. Reading the file whole to answer with eighty lines of it is the cost the
+     * eighty lines of it is the cost the server's own reader was rewritten to stop paying.
-     * server's own reader was rewritten to stop paying.
      *
      * Damage anywhere but at the tail of the open chunk was not written by this code, and there is
      * no honest way to say what a chunk covers with a line of it unreadable -- so it discards the
@@ -433,8 +405,8 @@ class SessionCache(
                 }
                 rename(existing.file, existing.first, existing.end)
             }
-        // A chunk that was created and never written to would otherwise be left behind under a
+        // A chunk that was created and never written to would otherwise be left behind under a name
-        // name a second one is about to want; it covers nothing, so nothing is lost with it.
+        // a second one is about to want; it covers nothing, so nothing is lost with it.
         dir.listFiles().orEmpty().forEach {
             if (CHUNK_NAME.matchEntire(it.name)?.groupValues?.get(2) == "open" && it.length() == 0L)
                 it.delete()
@@ -480,12 +452,12 @@ class SessionCache(
      *
      * None of this is reported on screen: none of it changes what the screen shows -- every read
      * here has a network path beside it producing the same result -- and the reader has nothing to
-     * do about it. It is logged, and damage discards this session's cache, which is what makes the
+     * do about it. Damage discards this session's cache, which makes the next open an ordinary cold
-     * next open an ordinary cold one.
+     * one.
      */
     private fun <T> guard(ifBroken: T, body: () -> T): T =
-        // A disk that refused once will refuse again, once per delta, so the first refusal is
+        // A disk that refused once will refuse again, once per delta, so the first refusal is also
-        // also the last: this instance stops writing rather than logging a line a token.
+        // the last: this instance stops writing rather than logging a line a token.
         guardIo(
             ifBroken,
             warn,
@@ -515,8 +487,7 @@ private val TYPE_IN_LINE = Regex(""""type"\s*:\s*"([^"]*)"""")
  * One line's sequence number, or null when the line is not one of ours.
  *
  * A regex rather than a JSON parse, so that this file carries no parser and runs under the JVM
- * tests: the seq is the first field the server writes (`SeqEvent`'s declaration order, with the
+ * tests: the seq is the first field the server writes, so the first match is the top-level one.
- * event flattened after it), so the first match is the top-level one.
  */
 private fun seqOf(line: String): Long? = SEQ_IN_LINE.find(line)?.groupValues?.get(1)?.toLongOrNull()
 
@@ -536,11 +507,10 @@ private const val READ_BLOCK = 64 * 1024
  *
  * Every question the cache is asked is about the newest end of a chunk, and a live run reaches the
  * size of the conversation, so reading forwards means reading a transcript to answer with the last
- * eighty lines of it. This reads blocks from the end and stops where the caller stops.
+ * eighty lines of it.
  *
  * Splitting on bytes is safe because the separator is `\n`, which cannot occur inside a multi-byte
- * UTF-8 sequence; each line is decoded whole, so nothing is cut through a character. A missing file
+ * UTF-8 sequence; each line is decoded whole. A missing file yields nothing.
- * yields nothing, which is the same answer as an empty one.
  */
 private fun eachLineBackwards(file: File, onLine: (offset: Long, line: String) -> Boolean) {
     if (!file.isFile) return
@@ -581,8 +551,8 @@ private const val NEWLINE = '\n'.code.toByte()
  * Drops a final line that is not one of ours, by truncating the file to where it starts.
  *
  * This app having died mid-write is the one kind of damage that is repaired rather than discarded:
- * the tail of an append-only file is the only place a partial line can be, and everything before it
+ * the tail of an append-only file is the only place a partial line can be. A second bad line is not
- * is intact. A second bad line is not this, and is left for the read path to notice.
+ * this, and is left for the read path to notice.
  */
 private fun repairTail(file: File) {
     var truncateTo = -1L
@@ -598,9 +568,7 @@ private fun sizeOf(file: File): Long =
 
 /**
  * The disk half of [SessionCache.guard], shared with [TranscriptCache]'s own maintenance.
- *
+ * [onFailure] is what the caller does about it beyond answering [ifBroken].
- * [onFailure] is what the caller does about it beyond answering [ifBroken] -- for a session's
- * cache, giving up on writing.
  */
 private fun <T> guardIo(
     ifBroken: T,

app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptItems.kt

@@ -9,10 +9,9 @@ import kotlinx.coroutines.withContext
  *
  * Events are the only data source, and there is deliberately no second shape for history to drift
  * from: a page fetched backwards, a live frame, and a line read out of this phone's own cache are
- * all the same events through the same parser. Since 2026-09-04 the cache is where most of them
+ * all the same events through the same parser. [TranscriptCache] stores the server's lines rather
- * come from on a session opened again -- see [TranscriptCache], which stores the server's lines
+ * than these rows for exactly that reason -- a row is a rendering, and its shape changes whenever
- * rather than these rows for exactly that reason: a row is a rendering, and its shape changes
+ * this file does.
- * whenever this file does.
  */
 @Immutable
 sealed class TranscriptItem {
@@ -24,10 +23,8 @@ sealed class TranscriptItem {
      * list is addressed by position: whatever somebody had scrolled to keeps its index while the
      * content underneath it slides, which reads as the view scrolling on its own.
      *
-     * A seq is the right identity because it is what the transcript itself is ordered by, it never
+     * A row built from several events keeps the seq of the first, so it holds still while the rest
-     * changes, and it is already carried by every event. A row built from several events -- a
+     * of it arrives.
-     * streaming message, a tool call and its result -- keeps the seq of the first, so it holds
-     * still while the rest of it arrives.
      */
     abstract val seq: Long
 
@@ -35,10 +32,8 @@ sealed class TranscriptItem {
      * This item's identity on screen, which is its [seq] for everything that has one of its own.
      *
      * Here rather than in [TranscriptRow.Single] because the two items that need something else are
-     * the two that know why: a tool call is named after its run, and a peer note is *sorted* by the
+     * the two that know why. Asking each item what it is called is also what stops the next such
-     * turn it started rather than by where it arrived. Asking each item what it is called is also
+     * item being missed -- a `when` over concrete types would have to gain a case, silently.
-     * what stops the next such item being missed -- a `when` over concrete types in the row would
-     * have to gain a case, silently, and nothing says when it did not.
      */
     open val key: Any
         get() = seq
@@ -59,15 +54,13 @@ sealed class TranscriptItem {
          * What it buys is the split. [transcriptUnits] keeps the newest reply whole because a
          * streaming reply's text changes per delta and splitting a changing text is a parse per
          * delta -- but "newest" outlives the turn, so a session that ends on a long reply was
-         * drawing it as one item indefinitely, with every node of it alive. Measured on a Pixel 9
+         * drawing it as one item indefinitely. Measured on a Pixel 9 Pro XL: one 34,996px reply on
-         * Pro XL: one 34,996px reply on screen put the frame's draw phase at 13.8ms, 79% of it the
+         * screen put the frame's draw phase at 13.8ms, 79% of it framework bookkeeping.
-         * framework's own bookkeeping, which grows with alive nodes.
          *
-         * Folded from the status event that ended the turn, rather than read off the screen's
+         * Folded from the status event that ended the turn rather than read off the screen's
          * status, because rows only change through the held-events gate: the split changes the
          * newest row's list identity, and doing that from a status flip while somebody is reading
-         * inside that reply would step the list under them. An event has to wait for the reader to
+         * inside that reply would step the list under them.
-         * be at the newest end; a screen state does not.
          */
         val settled: Boolean = false,
     ) : TranscriptItem()
@@ -79,11 +72,10 @@ sealed class TranscriptItem {
          * The run of adjacent calls this one belongs to, named once when the call is folded in and
          * never recomputed.
          *
-         * Carried rather than derived because a run can gain members at *either* end -- a new call
+         * Carried rather than derived because a run can gain members at *either* end, so no
-         * arriving beside it, or a page of history arriving in front of it -- so no function of its
+         * function of its current members is stable. It is the first call's id at the moment the
-         * current members is stable. It is the first call's id at the moment the run started, which
+         * run started, which is a name rather than a description: [joinPages] hands it to older
-         * is a name rather than a description: [joinPages] hands it to older calls that turn out to
+         * calls that turn out to belong to the same run.
-         * belong to the same run, instead of renaming the run they joined.
          */
         val runId: String,
         val tool: String,
@@ -94,19 +86,16 @@ sealed class TranscriptItem {
          * The questions this call is waiting on, in the order they were asked.
          *
          * On the call's own row rather than beside it: an ask used to arrive as a second card
-         * repeating the input verbatim, so the reader saw the same command twice and had to work
+         * repeating the input verbatim, so the reader saw the same command twice. The backend says
-         * out that it was one event. The backend says which call a question is about, so this is a
+         * which call a question is about, so this is a fact rather than a match on the input.
-         * fact rather than a match on the input.
          *
-         * A list because AskUserQuestion asks up to four at once, and they are one decision to make
+         * A list because AskUserQuestion asks up to four at once, and a permission is the case of
-         * -- a permission is the case of exactly one, not a different shape.
+         * exactly one rather than a different shape.
          */
         val asks: List<QuestionCard> = emptyList(),
         /**
-         * Images this call's result carried, drawn under it.
+         * Images this call's result carried, drawn under it. Beside it they had to be paired by
-         *
+         * position, and position is what a page boundary breaks.
-         * Beside it they had to be paired by position, and position is the thing a page boundary
-         * breaks -- a screenshot loaded on one page and its call on the next read as unrelated.
          */
         val images: List<String> = emptyList(),
     ) : TranscriptItem() {
@@ -134,9 +123,8 @@ sealed class TranscriptItem {
     data class ImageItem(override val seq: Long, val ref: String) : TranscriptItem()
 
     /**
-     * A message another agent sent this session.
+     * A message another agent sent this session. Its own row rather than a [UserMsg]: see
-     *
+     * [PeerMessageRow] for why the voice matters.
-     * Its own row rather than a [UserMsg]: see [PeerMessageRow] for why the voice matters.
      */
     data class PeerNote(
         override val seq: Long,
@@ -145,11 +133,9 @@ sealed class TranscriptItem {
         /**
          * The seq of the event this note came in on, which is what makes it itself.
          *
-         * [seq] is where the note *sorts*, and [placePeerNote] sets it to the seq the turn began at
+         * [seq] is where the note *sorts*, and [placePeerNote] sets it to the seq the turn began
-         * so the note is drawn above the reply it caused. Two messages that arrive during one turn
+         * at. Two messages that arrive during one turn therefore share a seq -- and sharing an
-         * therefore share a seq -- and sharing an identity as well killed the app, because the
+         * identity as well killed the app, because the list refuses two items with one key.
-         * transcript list refuses two items with one key. Two agents writing to a session mid-turn
-         * is an ordinary afternoon, not a corner.
          */
         val arrived: Long = seq,
     ) : TranscriptItem() {
@@ -158,10 +144,9 @@ sealed class TranscriptItem {
     }
 
     /**
-     * A command the session ran on itself -- `/compact`, `/rename`.
+     * A command the session ran on itself -- `/compact`, `/rename`. Kept in the transcript rather
-     *
+     * than only shown while it waits, because it explains what follows: a conversation that
-     * Kept in the transcript rather than only shown while it waits, because it explains what
+     * suddenly has half the context, or a session with a new name.
-     * follows: a conversation that suddenly has half the context, or a session with a new name.
      */
     data class CommandRow(override val seq: Long, val text: String) : TranscriptItem()
 
@@ -170,7 +155,6 @@ sealed class TranscriptItem {
 
     /**
      * A clear that happened: everything above it left the session's context and stayed on screen.
-     *
      * Carries only its position, because that is all it means.
      */
     data class ClearedNote(override val seq: Long) : TranscriptItem()
@@ -179,12 +163,12 @@ sealed class TranscriptItem {
      * A compaction that happened, and what it recovered.
      *
      * In the transcript rather than only in the status line, because the status is gone the moment
-     * it finishes and this is the part worth keeping: it is the explanation for a gap in the
+     * it finishes and this is the part worth keeping: the explanation for a gap in the
-     * conversation, and for a minute or two in which the session was busy with nothing to show.
+     * conversation.
      *
-     * The wire also says what triggered it, and this deliberately does not carry that: the row says
+     * The wire also says what triggered it, and this deliberately does not carry that -- the row
-     * the two sizes and nothing else (see [compactionSummary]), so keeping the trigger here would
+     * says the two sizes and nothing else, so keeping the trigger would be a field nothing can
-     * be a field nothing can read.
+     * read.
      */
     data class CompactedNote(
         override val seq: Long,
@@ -197,16 +181,13 @@ sealed class TranscriptItem {
  * The run a call joins: the one it lands next to, or a new one named after itself.
  *
  * Only ever consulted when the call is first folded in. That is what makes the name stable -- a run
- * keeps whatever it was called when it started, however many calls arrive at either end of it
+ * keeps whatever it was called when it started, however many calls arrive at either end afterwards.
- * afterwards.
  *
  * A question to the reader is in a run of its own, which is what puts it on the transcript as a row
- * rather than inside a collapsed "Called 6 tools" card. Two things follow from being alone: it is
+ * rather than inside a collapsed "Called 6 tools" card. Two things follow: it is always visible,
- * always visible, since a run of one is drawn as itself rather than as a group; and the calls
+ * since a run of one is drawn as itself; and the calls around it fall into a group before it and a
- * around it fall into a group before it and a group after it, so where the reader was asked
+ * group after it, so where the reader was asked something is legible in the shape of the transcript
- * something is legible in the shape of the transcript without opening anything. It ends the run
+ * without opening anything.
- * before it as well as starting a fresh one after -- the moment somebody was asked is a boundary in
- * the work, not a gap in the middle of one run.
  */
 private fun runIdFor(items: List<TranscriptItem>, id: String, tool: String): String {
     val previous = items.lastOrNull() as? TranscriptItem.ToolRun ?: return id
@@ -219,31 +200,23 @@ private fun runIdFor(items: List<TranscriptItem>, id: String, tool: String): Str
  * boundary cut in two.
  *
  * Two things straddle a boundary: a tool call separated from its result, and a message separated
- * from the rest of itself. Both were one thing before the transcript was cut into pages, and both
+ * from the rest of itself. Both were one thing before the transcript was cut into pages.
- * have to be one thing again -- a reply drawn as two messages is the same defect as a call drawn
- * twice, arriving from the same cause.
  *
  * A boundary lands wherever it lands, and roughly half the time that is between a call and its
  * result. The newer page then holds a `ToolEnd` whose start it never saw, which [foldEvent] draws
  * as a row of its own -- correctly, because a call that renders as nothing is indistinguishable
  * from one that never happened. When the older page arrives it brings the real `ToolStart`, and
- * concatenating the two lists left *both*: the same call twice, once as a proper card and once as a
+ * concatenating the two lists left *both*: the same call twice.
- * nameless placeholder. Visible as a run of four calls reporting "Called 5 tools", and worse than
- * the miscount -- the extra row is at the join, so it also moves everything the reader was looking
- * at.
  *
  * Merged by the call's own id rather than by position, because position is exactly what a page
- * boundary destroys. The older row wins on what a start knows (the tool's name, its input) and the
+ * boundary destroys. The older row wins on what a start knows and the newer on what an end knows,
- * newer on what an end knows (the output, and whether it finished), which is the only way round
+ * which is the only way round that loses nothing.
- * that loses nothing.
  *
  * The third thing is the *run*, and it is the one that used to be missed. Every page ends up here,
  * but [adoptRun] only ran on the path where a split call had been found -- so the boundary that
- * falls cleanly between two finished calls, which is most of them, went straight to concatenation
+ * falls cleanly between two finished calls, which is most of them, left the older page's calls
- * and left the older page's calls under the run name they were folded with. On screen: one run of
+ * under the run name they were folded with. On screen: one run of tool calls drawn as two groups,
- * tool calls drawn as two groups, with the seam wherever the reader happened to have paged. The two
+ * with the seam wherever the reader happened to have paged.
- * early returns were an optimisation on a list the size of one page, and they were skipping work
- * rather than saving it.
  */
 fun joinPages(earlier: List<TranscriptItem>, later: List<TranscriptItem>): List<TranscriptItem> {
     val (older, newer) = healSplitMessage(earlier, later)
@@ -276,15 +249,13 @@ fun joinPages(earlier: List<TranscriptItem>, later: List<TranscriptItem>): List<
 /**
  * Rejoins a message the page boundary cut, and hands back the two pages to concatenate.
  *
- * [foldEvent] never leaves two assistant messages next to each other inside one page -- deltas
+ * [foldEvent] never leaves two assistant messages next to each other inside one page, so two
- * accumulate into the message before them -- so two meeting at a join are always the two halves of
+ * meeting at a join are always the two halves of one reply, and leaving them apart drew a single
- * one reply, and leaving them apart drew a single answer as two, with a paragraph break through the
+ * answer as two with a paragraph break through the middle of a sentence.
- * middle of a sentence.
  *
- * The newer half keeps its identity, for the reason [adoptRun] gives: it is the row already on
+ * The newer half keeps its identity, for the reason [adoptRun] gives. It grows by what the older
- * screen, and renaming that is how the list loses its anchor. It grows by what the older half
+ * half brings, which is safe here and nowhere else -- the join is at the oldest end of what is
- * brings, which is safe here and nowhere else -- the join is at the oldest end of what is loaded,
+ * loaded, so the growth extends off the top of the screen.
- * so the growth extends off the top of the screen, away from the row the list anchors to.
  */
 private fun healSplitMessage(
     earlier: List<TranscriptItem>,
@@ -302,19 +273,18 @@ private fun healSplitMessage(
  * Hands the older calls at the join the name of the run they are joining.
  *
  * The two pages were folded separately, so a run split by the boundary came back as two runs with
- * two names. Naming the joined run after the *older* half would be the obvious way round and is the
+ * two names. Naming the joined run after the *older* half would be the obvious way round and is
- * wrong one: the newer half is the part already on screen, and renaming it is renaming the row the
+ * wrong: the newer half is the part already on screen, and renaming it is renaming the row the
- * reader is looking at, which is how a list loses its anchor and steps under them. So the arriving
+ * reader is looking at, which is how a list loses its anchor.
- * calls take the name of the ones already there, and nothing visible changes identity.
  */
 private fun adoptRun(
     earlier: List<TranscriptItem>,
     later: List<TranscriptItem>,
 ): List<TranscriptItem> {
     val first = later.firstOrNull() as? TranscriptItem.ToolRun ?: return earlier
-    // A question is in a run of its own on both sides of the join, the same as it would be had
+    // A question is in a run of its own on both sides of the join, the same as it would be had the
-    // the two pages been folded as one -- see `runIdFor`. Without this the heal would merge a
+    // two pages been folded as one. Without this the heal would merge a group straight through the
-    // group straight through the row the reader was asked something on.
+    // row the reader was asked something on.
     if (first.tool == ASK_USER_QUESTION) return earlier
     val joining = first.runId
     val tail = earlier.takeLastWhile {
@@ -329,10 +299,8 @@ private fun adoptRun(
  * A peer message goes above the turn it started, not where it happened to arrive.
  *
  * The live Claude Code path cannot record it in place: the CLI says nothing about a peer message
- * until the turn's `result`, so the event lands below the whole reply it caused -- the answer
+ * until the turn's `result`, so the event lands below the whole reply it caused. The server stamps
- * printed above the question. The server stamps it with where that turn began
+ * it with where that turn began and the note takes that seq.
- * ([SessionEvent.PeerMessage.turnStart]) and the note takes that seq, so it sorts into the list
- * where it belongs rather than being drawn out of order at the end.
  *
  * Taking the turn's opening seq as its own is also what keeps the list sorted, which anchors and
  * paging both depend on. It is only a *position*, though, and the note keeps its own arrival seq as
@@ -340,8 +308,7 @@ private fun adoptRun(
  * seq belongs to a status change and a status draws no row -- true, and it answered the wrong
  * question: what two notes stamped with the same turn collide with is each other.
  *
- * Without a stamp -- a message replayed out of a session file, which is already in the right place
+ * Without a stamp -- a message replayed out of a session file -- it stays where it arrived.
- * -- it stays where it arrived.
  */
 private fun placePeerNote(
     items: List<TranscriptItem>,
@@ -360,15 +327,14 @@ private fun placePeerNote(
  * The calls the note now sits in front of, renamed if they were sharing a run with the calls behind
  * it.
  *
- * A run is named from what a call landed next to (see [runIdFor]), and nothing there knows about
+ * A run is named from what a call landed next to, and nothing there knows about turns -- so a turn
- * turns -- so a turn opening with a tool call, straight after one that ended with one, folds them
+ * opening with a tool call, straight after one that ended with one, folds them into a single run.
- * into a single run. Left alone, [groupToolRuns] would flush at the note and hand both halves the
+ * Left alone, [groupToolRuns] would flush at the note and hand both halves the same name: two rows
- * same name: two rows with one key, which a keyed list cannot draw at all.
+ * with one key, which a keyed list cannot draw at all.
  *
  * The later half is the one renamed, which is the opposite of a page join ([adoptRun]) and right
- * for the opposite reason. There the two halves were always one run and the newer was already on
+ * for the opposite reason: there the two halves were always one run, here they were never one
- * screen; here they were never one turn's work, and both halves change appearance at the same
+ * turn's work.
- * moment the note appears between them.
  */
 private fun splitRun(tail: List<TranscriptItem>, behind: String?): List<TranscriptItem> {
     val first = tail.firstOrNull() as? TranscriptItem.ToolRun ?: return tail
@@ -406,12 +372,10 @@ fun foldEvent(items: List<TranscriptItem>, entry: SeqEvent): List<TranscriptItem
                 )
         is SessionEvent.ToolUpdate -> updateTool(items, event.id) { it.copy(output = event.output) }
         is SessionEvent.ToolEnd ->
-            // Created when its start is not here, rather than dropped. A
+            // Created when its start is not here, rather than dropped. A fold that only ever
-            // fold that only ever *updates* loses the whole call when the
+            // *updates* loses the whole call when the start fell outside the loaded window, and a
-            // start fell outside the loaded window, and a tool call that
+            // tool call that renders as nothing is indistinguishable from one that never happened.
-            // renders as nothing is indistinguishable from one that never
+            // Loading the page before this one replaces the row with the real thing.
-            // happened. The name is unknown from an end alone; loading the
-            // page before this one replaces the row with the real thing.
             if (items.any { it is TranscriptItem.ToolRun && it.id == event.id }) {
                 updateTool(items, event.id) { it.copy(output = event.output, done = true) }
             } else {
@@ -419,9 +383,8 @@ fun foldEvent(items: List<TranscriptItem>, entry: SeqEvent): List<TranscriptItem
                     TranscriptItem.ToolRun(
                         entry.seq,
                         event.id,
-                        // The name is not known from an end alone, so a call that was an ask
+                        // The name is not known from an end alone, so a call that was an ask cannot
-                        // cannot be recognised as one here; loading the page before this
+                        // be recognised as one here; the page before this replaces the row.
-                        // replaces the row with the real thing, which is when it splits out.
                         runIdFor(items, event.id, "tool"),
                         "tool",
                         "",
@@ -440,9 +403,8 @@ fun foldEvent(items: List<TranscriptItem>, entry: SeqEvent): List<TranscriptItem
                     event.multiSelect,
                     emptyList(),
                 )
-            // A question with no tool behind it -- AskUserQuestion, or an ask
+            // A question with no tool behind it -- AskUserQuestion, or an ask whose call fell
-            // whose call fell outside the loaded window -- is a card of its
+            // outside the loaded window -- is a card of its own.
-            // own, which is what every question was before this.
             if (
                 event.about != null &&
                     items.any { it is TranscriptItem.ToolRun && it.id == event.about }
@@ -453,9 +415,9 @@ fun foldEvent(items: List<TranscriptItem>, entry: SeqEvent): List<TranscriptItem
             }
         }
         is SessionEvent.Answered ->
-            // Resolved wherever it is drawn: a card of its own, or a tool
+            // Resolved wherever it is drawn: a card of its own, or a tool row's ask. Missing the
-            // row's ask. Missing the second left an Allow/Deny pair live on
+            // second left an Allow/Deny pair live on a question already answered from another
-            // a question already answered from another device.
+            // device.
             items.map {
                 when {
                     it is TranscriptItem.QuestionCard && it.id == event.id ->
@@ -475,20 +437,19 @@ fun foldEvent(items: List<TranscriptItem>, entry: SeqEvent): List<TranscriptItem
         is SessionEvent.CommandSent -> items + TranscriptItem.CommandRow(entry.seq, event.text)
         // Screen-level state, not transcript rows -- see SessionScreen.
         is SessionEvent.CommandQueued -> items
-        // No row of its own: a message that is still waiting is drawn as a pending bubble below
+        // No row of its own: a message that is still waiting is drawn as a pending bubble below the
-        // the transcript, and becomes an ordinary one where the session read it.
+        // transcript, and becomes an ordinary one where the session read it.
         is SessionEvent.MessageQueued -> items
-        // The bubble goes away and nothing takes its place: the message was never read, so there
+        // The bubble goes away and nothing takes its place: the message was never read, so there is
-        // is nothing it belongs above.
+        // nothing it belongs above.
         is SessionEvent.MessageDropped -> items
         is SessionEvent.Settings -> items
         is SessionEvent.Status -> settleReply(items, event.state)
         is SessionEvent.Error -> items + TranscriptItem.ErrorMsg(entry.seq, event.message)
         is SessionEvent.Image ->
-            // Under the call that produced it when there is one, and a row of
+            // Under the call that produced it when there is one, and a row of its own when there is
-            // its own when there is not -- a person's own attachment belongs
+            // not -- a person's own attachment belongs to no call, and neither does one whose call
-            // to no call, and neither does one whose call fell outside the
+            // fell outside the loaded window.
-            // loaded window.
             if (
                 event.about != null &&
                     items.any { it is TranscriptItem.ToolRun && it.id == event.about }
@@ -508,9 +469,8 @@ fun foldEvent(items: List<TranscriptItem>, entry: SeqEvent): List<TranscriptItem
 /**
  * A status saying the session stopped working is the moment its newest reply is finished.
  *
- * See [TranscriptItem.AssistantMsg.settled] for what the mark buys and why it is made here in the
+ * See [TranscriptItem.AssistantMsg.settled]. Status changes are transcript events with seqs of
- * fold. Status changes are transcript events with seqs of their own, so a replayed session settles
+ * their own, so a replayed session settles its replies the same way a live one does.
- * its replies the same way a live one does.
  */
 private fun settleReply(items: List<TranscriptItem>, state: String): List<TranscriptItem> {
     if (sessionWorking(state)) return items
@@ -533,8 +493,7 @@ private fun updateTool(
  * The default dispatcher sizes itself to the machine, which is right for work somebody is waiting
  * on and wrong for work nobody is. A page of history is hundreds of parses arriving at once, and
  * taking every core for them leaves the thread that draws the frame queueing behind one -- measured
- * on a Pixel 9 Pro XL as 21ms of `waited` at the 90th percentile, which is the frame failing to
+ * on a Pixel 9 Pro XL as 21ms of `waited` at the 90th percentile.
- * *start* rather than taking too long once it had.
  */
 @OptIn(kotlinx.coroutines.ExperimentalCoroutinesApi::class)
 private val parsingThreads = Dispatchers.Default.limitedParallelism(2)
@@ -543,37 +502,33 @@ private val parsingThreads = Dispatchers.Default.limitedParallelism(2)
  * Parses the markdown among [rows], off whatever thread is drawing.
  *
  * Called where a page of transcript is folded rather than where a row is composed, which is the
- * whole point: the work happens seconds before the reader reaches the rows it was done for. See
+ * whole point: the work happens seconds before the reader reaches the rows it was done for.
- * [ParsedReplies].
  *
  * What is warmed mirrors what the rows draw -- each prose part of a reply, a memory note, a peer
- * message, every one of them whole, since every piece of a message is drawn from its one parse --
+ * message -- because a string warmed under a key no row ever looks up is a miss that nothing
- * because a string warmed under a key no row ever looks up is a miss that nothing reports; see
+ * reports; see [transcriptUnits], which is the flatten this has to agree with. It reads the same
- * [transcriptUnits], which is the flatten this has to agree with. It reads the same
  * [ParsedReplies.partsOf] cache the flatten does, so a message is scanned once however many pages
- * hand it back through here, while the whole loaded transcript crosses this on every page.
+ * hand it back through here.
  *
  * Every kind of row that draws markdown belongs in the `when` below. That is the rule the peer
  * message was missing: this used to filter for assistant replies alone, so the one row type nobody
- * had thought about paid its whole parse in the frame it appeared in, with no counter saying which
+ * had thought about paid its whole parse in the frame it appeared in.
- * row it was.
  */
 suspend fun warm(replies: ParsedReplies, rows: List<TranscriptItem>) {
     withContext(parsingThreads) {
         val texts = rows.flatMap { row ->
             when (row) {
                 is TranscriptItem.AssistantMsg -> replies.partsOf(row.text).map { it.text }
-                // A message from another agent is markdown too, and it is the longest thing
+                // A message from another agent is markdown too, and it is the longest thing in a
-                // in a transcript often enough that leaving it out was the whole of why one
+                // transcript often enough that leaving it out was the whole of why one cost a fifth
-                // cost a fifth of a second to open: it was the only markdown in the app
+                // of a second to open.
-                // parsed on the thread that draws.
                 is TranscriptItem.PeerNote -> listOf(row.text)
                 else -> emptyList()
             }
         }
         if (texts.isNotEmpty()) replies.warm(texts)
-        // After the parses exist, not before: [ParsedReplies.splitReady] is the flatten's
+        // After the parses exist, not before: [ParsedReplies.splitReady] is the flatten's licence
-        // licence to draw these as blocks on the composing thread.
+        // to draw these as blocks on the composing thread.
         rows.forEach { if (it is TranscriptItem.AssistantMsg) replies.markSplitReady(it.text) }
     }
 }

app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptList.kt

@@ -25,31 +25,24 @@ import androidx.compose.ui.unit.dp
  * zero is the newest content and sits at the bottom, so a message arriving extends the end the
  * viewport is pinned to and following it is not an effect -- and a page of older history lands at
  * indices past everything visible, which moves nothing on screen. The keyboard is the same case
- * from the other side: the viewport shrinks and the anchored item stays against its bottom edge. A
+ * from the other side: the viewport shrinks and the anchored item stays against its bottom edge.
- * conversation shorter than the screen stacks from the bottom, hanging from the composer.
  *
  * The lazy list is also the whole of the windowing. Only what is near the viewport is composed and
  * alive, so the per-frame cost is bounded by the screen rather than by how much is loaded -- the
  * property a plain column here had to approximate with retained ranges and stand-in spacers, each
- * of which was a way to flicker. An item the framework composes is drawn the same frame it is
+ * of which was a way to flicker.
- * placed, and an item off screen is not a node at all.
  *
  * What keeps a unit's arrival cheap enough to happen mid-fling: a unit is at most one block of a
- * reply, and its parse is already made by [warm] before the fold that introduces it -- so entering
+ * reply, and its parse is already made by [warm] before the fold that introduces it.
- * composition costs laying out one paragraph, not parsing a message.
  *
- * The whole list sits in a [SelectionContainer], which is what makes every word in the transcript
+ * The whole list sits in a [SelectionContainer], which is what makes every word selectable by the
- * selectable by the platform's own press-and-hold. Here rather than at each place text is drawn: a
+ * platform's own press-and-hold. Here rather than at each place text is drawn: a transcript is one
- * transcript is one body of text to a reader, and a container per row would mean a selection could
+ * body of text to a reader, and a container per row would mean a selection could never cross from a
- * never cross from a reply into the tool output that follows it -- and would leave whatever was
+ * reply into the tool output that follows it -- and would leave whatever was drawn without one
- * drawn without one silently unselectable, which is a state nothing on screen reports. Rows keep
+ * silently unselectable. Rows keep their tap handlers: selection is a long press.
- * their tap handlers: selection is a long press, and the container passes an ordinary click through
- * to the card under it.
  *
  * [selection] is the container's own state, held by the caller rather than made here, because the
- * rows have to be able to ask whether anything is selected before they act on a tap -- a tap whose
+ * rows have to be able to ask whether anything is selected before they act on a tap.
- * job is to put a selection away is not also a tap on the card under it. See the caller's
- * `expanding`.
  */
 @Composable
 fun TranscriptList(
@@ -69,8 +62,7 @@ fun TranscriptList(
             modifier =
                 // Timed in two halves because the frame's draw phase is where Compose's measurement
                 // lands, and "draw is high while nothing is being recorded" does not say which
-                // half;
+                // half. Measure includes composing the items that scrolled in.
-                // see [drawAccounting]. Measure includes composing the items that scrolled in.
                 modifier
                     .layout { measurable, constraints ->
                         val started = System.nanoTime()
@@ -104,8 +96,7 @@ fun TranscriptList(
             }
             // Standing in for everything not fetched yet. Only here while there is more -- its
             // appearance at the top edge is also roughly when the next page is asked for, so what
-            // it
+            // it reports is a fetch in flight rather than an end reached.
-            // reports is a fetch in flight rather than an end reached.
             if (moreHistory) {
                 item(key = "history", contentType = "history") {
                     Box(Modifier.fillMaxWidth().padding(vertical = 24.dp)) {

app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptSource.kt

@@ -9,14 +9,12 @@ import java.util.concurrent.atomic.AtomicReference
  * rest.
  *
  * One seam rather than a cache the screen has to remember to consult. Everything it fetched before
- * -- the opening window, the pages it scrolls back through, the span an anchor restore reaches for
+ * is asked of this, and everything the server sends is written into the cache on the way past, so
- * -- is asked of this, and everything the server sends is written into the cache on the way past,
+ * the screen never learns which side answered. What it does learn, through [DebugStats], is how
- * so the screen never learns which side answered. What it does learn, through [DebugStats], is how
+ * often each one did.
- * often each one did, which is how the saving is measured.
  *
- * See TRANSCRIPT_CACHE.md. The one rule worth keeping in mind here: the cache is never
+ * See TRANSCRIPT_CACHE.md. The one rule worth keeping in mind: the cache is never load-bearing.
- * load-bearing. Every read has a network path beside it producing the same result, so a missing,
+ * Every read has a network path beside it producing the same result.
- * evicted or damaged cache degrades to exactly what this screen did before it existed.
  */
 class TranscriptSource(
     private val settings: ServerSettings,
@@ -51,18 +49,17 @@ class TranscriptSource(
      *
      * The screen must not resume a stream from a cached seq unless it is the same conversation. A
      * transcript is append-only in ordinary use, but the file can be replaced or truncated -- a
-     * sandbox re-seeded with the same ids, a backup restored, a directory deleted and the session
+     * sandbox re-seeded with the same ids, a backup restored, a session re-imported -- and the
-     * re-imported -- and the server's catch-up on such a file would hand this phone a continuation
+     * server's catch-up on such a file would hand this phone a continuation of a *different*
-     * of a *different* conversation, spliced onto the cached one with no seam. That is the worst
+     * conversation, spliced onto the cached one with no seam. Caught with one request of a few
-     * thing this feature can do, and it is caught with one request of a few hundred bytes, in the
+     * hundred bytes, in the slot the opening page's request used to be in.
-     * slot the opening page's request used to be in.
      *
      * False purges the cache and means "open cold". A throw is the server not being askable, which
-     * is neither: the cached rows stay on screen, the failure goes on the stream banner, and the
+     * is neither: the cached rows stay on screen and the caller tries again on the reconnect
-     * caller tries again on the stream's own reconnect schedule.
+     * schedule.
      *
      * What this cannot see is a line changed in the middle of the file with the tail intact. That
-     * is what the Reload button in session settings is for, and its caption says so.
+     * is what the Reload button in session settings is for.
      */
     suspend fun probe(): Boolean {
         val tail = cache.tail() ?: return false
@@ -100,8 +97,7 @@ class TranscriptSource(
      * row count takes it -- a single reply is hundreds of lines -- so a page fetched after the
      * reader has been away would run straight past the cached run and overlap it, and an
      * overlapping page cannot be stored. Told where this phone's copy starts, the server stops
-     * there instead, the gap is closed with exactly the bytes it was wide, and the history behind
+     * there instead.
-     * it is served locally from then on.
      */
     suspend fun page(before: Long, limit: Int, coalesce: Boolean): List<SeqEvent> {
         cache.page(before, limit, rows = coalesce)?.let { lines ->
@@ -169,10 +165,8 @@ private const val OPENING_WINDOW = 80
  *
  * Under `cacheDir` because that is exactly what it is for: bytes the phone can regenerate from the
  * server, which Android may delete under storage pressure without asking. Keyed by host and port
- * because two servers can hold a session with the same id -- the sandbox and the real server, or a
+ * because two servers can hold a session with the same id, and a line from one shown against the
- * re-enrolment -- and a line from one shown against the other is the whole invariant broken. `v1`
+ * other is the whole invariant broken. `v1` is the layout's version.
- * is the layout's version: a change to it bumps the segment, and a directory of another version is
- * deleted the first time this is called.
  */
 fun cacheRoot(context: Context, settings: ServerSettings): File {
     val transcripts = File(context.cacheDir, "transcripts")

app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptUnits.kt

@@ -12,8 +12,7 @@ import androidx.compose.ui.unit.dp
  * at the moment it scrolls into view, and that cost is proportional to the item -- a reply can be
  * twenty-five screens of markdown, which as one item is a hundred-millisecond frame exactly when
  * the list is moving fastest. A *block* is a paragraph, a fence, a table: bounded, so the worst
- * frame is bounded. This is the piece that was missing when a lazy list was last tried here; the
+ * frame is bounded. This is the piece that was missing when a lazy list was last tried here.
- * block splitting existed only inside the row, where the list could not see it.
  *
  * Everything else about the row model is unchanged: rows come from [groupToolRuns], and a unit
  * points back at its row. The list draws units; anchors and paging still speak seq.
@@ -27,10 +26,9 @@ sealed class TranscriptUnit {
     abstract val seq: Long
 
     /**
-     * This unit's position within its row, counted from the row's oldest end.
+     * This unit's position within its row, counted from the row's oldest end. What a saved scroll
-     *
+     * position carries besides the seq: a reply split into forty blocks needs more than "somewhere
-     * What a saved scroll position carries besides the seq: a reply split into forty blocks needs
+     * in this row" to put a reader back where they stopped.
-     * more than "somewhere in this row" to put a reader back where they stopped.
      */
     abstract val ordinal: Int
 
@@ -66,15 +64,13 @@ sealed class TranscriptUnit {
      *
      * A peer message is the one row whose *opened* size is unbounded -- these are the longest
      * things a transcript holds -- so it is flattened the same way a settled reply is, and for the
-     * same reason: as one item, every block of it is composed, measured, placed and kept alive
+     * same reason. Measured on the emulator, opening a 43KB one took the transcript's share of the
-     * while any part of it is on screen. Measured on the emulator, opening a 43KB one took the
+     * draw phase from 0.81ms a frame to 3.85ms, and the framework's own per-frame bookkeeping from
-     * transcript's share of the draw phase from 0.81ms a frame to 3.85ms, and the framework's own
+     * 0.39ms to 3.15ms.
-     * per-frame bookkeeping -- which grows with how many nodes are *alive* -- from 0.39ms to
-     * 3.15ms.
      *
      * The card is drawn in pieces rather than given up: a filled Material card is elevation zero,
      * so it has no shadow to break, and each piece paints the same fill with only the corners it
-     * owns. See [PeerHeadRow] and [PeerBlockRow].
+     * owns.
      */
     data class PeerHead(
         override val seq: Long,
@@ -84,8 +80,7 @@ sealed class TranscriptUnit {
     ) : TranscriptUnit() {
         /**
          * The note's own key, so opening and shutting does not change what the list is anchored on
-         * -- and so two notes stamped with one turn's seq are still two items. See
+         * -- and so two notes stamped with one turn's seq are still two items.
-         * [TranscriptItem.PeerNote].
          */
         override val key: Any
             get() = item.key
@@ -119,8 +114,7 @@ sealed class TranscriptUnit {
      *
      * A user message is plain text, so cutting it costs a scan rather than a parse -- but the
      * reason is the same as for a settled reply: as one item, a pasted log is a hundred thousand
-     * pixels of `Text` whose layout lands in the frame the row scrolls into. Measured as the
+     * pixels of `Text` whose layout lands in the frame the row scrolls into.
-     * `measure: the whole transcript ... 112.1ms worst` in an otherwise smooth report.
      */
     data class UserChunk(
         override val seq: Long,
@@ -152,14 +146,11 @@ sealed class TranscriptUnit {
  * The rows flattened into list units, newest first -- index zero is the item at the bottom of the
  * screen, which is what a reversed lazy list calls the start.
  *
- * Every settled reply is cut into its pieces ([pieces], via the caches on [replies] so a message is
+ * Every settled reply is cut into its pieces (via the caches on [replies] so a message is only ever
- * only ever cut once), and so is an *opened* peer message -- [openNotes] is which ones those are,
+ * cut once), and so is an *opened* peer message -- [openNotes] is which ones those are. A shut one
- * which is why the flatten needs it. A shut one is a single heading and cannot be worth splitting.
+ * is a single heading and cannot be worth splitting. The reply still arriving stays whole: its text
- * The reply still arriving -- the newest row, until the status event that ends its turn marks it
+ * changes with every delta, and splitting it here would parse the whole message per delta on
- * [TranscriptItem.AssistantMsg.settled] -- stays whole: its text changes with every delta, and
+ * whichever thread is composing. Once settled it splits like every other reply, which is what
- * splitting it here would parse the whole message per delta on whichever thread is composing.
- * [AssistantMessage]'s own streaming path already parses deltas off the main thread and gives the
- * live message a layer per piece. Once settled it splits like every other reply, which is what
  * bounds the newest row's cost after a session ends on a long one.
  *
  * Runs per fold, so it must stay proportional to what is loaded with no parsing in it on the warm
@@ -200,8 +191,8 @@ fun transcriptUnits(
                 }
             }
         } else if (item is TranscriptItem.UserMsg && item.text.length > USER_SPLIT_CHARS) {
-            // A scan, not a parse, so it is cheap enough for the fold path -- and cached like
+            // A scan, not a parse, so it is cheap enough for the fold path -- and cached like the
-            // the markdown splits so the scan too happens once per message, not once per fold.
+            // markdown splits so the scan happens once per message rather than once per fold.
             val chunks = replies.chunksOf(item.text)
             chunks.forEachIndexed { at, chunk ->
                 units +=
@@ -252,8 +243,8 @@ fun transcriptUnits(
     }
     units.reverse()
     reportDuplicateKeys(units)
-    // Timed because this runs per fold on the composing thread: "loading messages feels bumpy"
+    // Timed because this runs per fold on the composing thread: "loading messages feels bumpy" is
-    // is this number growing, and it was invisible until it was written down.
+    // this number growing, and it was invisible until it was written down.
     DebugStats.record("units flattened", System.nanoTime() - started)
     return units
 }
@@ -261,9 +252,8 @@ fun transcriptUnits(
 /**
  * Whether this reply should be drawn as blocks: settled, or anywhere but the newest row.
  *
- * Wanting is not being ready -- the flatten also asks [ParsedReplies.splitReady], and the two
+ * Wanting is not being ready -- the flatten also asks [ParsedReplies.splitReady], and the two are
- * questions are separate because they are answered by different things: this one by the fold, the
+ * answered by different things: this one by the fold, the other by whether [warm] has run.
- * other by whether [warm] has run for the text. [unwarmedReplies] is the gap between them.
  */
 private fun splitWanted(item: TranscriptItem.AssistantMsg, index: Int, lastIndex: Int) =
     item.settled || index != lastIndex
@@ -272,8 +262,7 @@ private fun splitWanted(item: TranscriptItem.AssistantMsg, index: Int, lastIndex
  * The replies among [rows] that should draw as blocks but whose parses are not made yet.
  *
  * Normally empty: every page's rows are warmed before the fold lands. The one row that can be cold
- * is the reply that just finished streaming -- nothing warms live deltas, so at the moment its turn
+ * is the reply that just finished streaming -- nothing warms live deltas. The session screen warms
- * ends its split would cost a whole-message parse on the composing thread. The session screen warms
  * what this returns off-thread and re-flattens, so the whole-to-blocks swap always composes against
  * ready parses.
  */

app/androidApp/src/main/kotlin/com/example/aiapp/UniqueItems.kt

@@ -12,19 +12,15 @@ import androidx.compose.runtime.Composable
  * on the main thread -- so it is not an error the screen can show, it closes the app. That is a
  * disproportionate answer to a list with a repeat in it, and it lands on the reader rather than on
  * whoever produced the repeat: on 2026-08-31 the import list crashed on a Claude Code session id
- * recorded under two project directories, which is an ordinary state of a machine and not something
+ * recorded under two project directories, which is an ordinary state of a machine.
- * the phone did.
  *
  * Every list in this app keyed on an id keyed it on an id *the server chose*, so all of them shared
- * the hazard and none of them could rule it out locally. Hence one function they all go through
+ * the hazard and none could rule it out locally. Hence one function they all go through.
- * rather than a `distinctBy` remembered at each call site.
  *
- * Dropping the repeat is the right answer here because the key is the whole identity: two rows with
+ * Dropping the repeat is right here because the key is the whole identity: two rows with one id are
- * one id are two rows every action would treat as the same thing, so there is nothing to show about
+ * two rows every action would treat as the same thing. Where the duplicate means something, the fix
- * the second that the first is not already showing. Where the duplicate means something -- the
+ * belongs at the source, and this is only what stops a data problem from being a crash. It is
- * import list's did -- the fix belongs at the source, and this is only what stops a data problem
+ * counted so the render report says it happened rather than leaving a silently shorter list.
- * from being a crash. It is counted so the render report says it happened rather than leaving a
- * silently shorter list.
  *
  * The transcript's own list is deliberately not on this: its keys are made here rather than
  * received, and it is the one list where an extra pass over the items is measurable.

app/androidApp/src/main/kotlin/com/example/aiapp/UsageDialog.kt

@@ -27,17 +27,14 @@ import java.time.OffsetDateTime
  * A dialog rather than a screen. Usage is something you check *against* what you were reading --
  * "can I start this" is asked with the transcript still on screen -- and pushing a whole screen for
  * it took the session away to answer a question about the session. It also has no navigation of its
- * own: there is nothing here to open, so the only thing its Back could ever have meant was "put
+ * own, so the only thing its Back could ever have meant was "put this away".
- * this away", which is what dismissing does. The system back gesture dismisses it, since a `Dialog`
- * handles that itself.
  */
 @Composable
 fun UsageDialog(feed: UsageFeed, onDismiss: () -> Unit) {
-    // A plain Dialog rather than an AlertDialog, for the spacing alone. AlertDialog fixes the
+    // A plain Dialog rather than an AlertDialog, for the spacing alone. AlertDialog fixes the gaps
-    // gaps between its title, its content and its buttons at sizes meant for a sentence of prose
+    // between its title, content and buttons at sizes meant for a sentence of prose and a decision;
-    // and a decision; this is a dense read-out, and those gaps left a band of empty dialog above
+    // this is a dense read-out, and those gaps left a band of empty dialog above Close that was
-    // Close that was taller than a bar. Everything else here is what AlertDialog would have
+    // taller than a bar.
-    // drawn -- the same container colour, the same corner -- so nothing about it looks foreign.
     Dialog(onDismissRequest = onDismiss) {
         Surface(
             shape = MaterialTheme.shapes.extraLarge,
@@ -49,11 +46,9 @@ fun UsageDialog(feed: UsageFeed, onDismiss: () -> Unit) {
                     modifier = Modifier.fillMaxWidth(),
                 ) {
                     // Deliberately not subtitled with the provider this was opened from. These
-                    // numbers belong to an account on a particular machine, reported by whichever
+                    // numbers belong to an account on a particular machine -- naming the session's
-                    // paid service answered there -- naming the session's provider here made an
+                    // provider here made an echo session's screen read "echo" above a line reading
-                    // echo session's screen read "echo" above a line reading "claude", which is a
+                    // "claude". Each machine names itself and the service it came from.
-                    // claim about echo that nothing measured. Each machine names itself and the
-                    // service it came from, which is the true scope.
                     Text(
                         "Usage",
                         style = MaterialTheme.typography.headlineSmall,
@@ -69,10 +64,9 @@ fun UsageDialog(feed: UsageFeed, onDismiss: () -> Unit) {
                     }
                 }
                 Spacer(Modifier.height(8.dp))
-                // Scrolls rather than being trimmed: a machine can report any number of windows
+                // Scrolls rather than being trimmed: a machine can report any number of windows and
-                // and there can be any number of machines, and a dialog is the one place where
+                // there can be any number of machines, and a dialog is the one place where running
-                // running out of room is silent. `fill = false` so a short read-out keeps a short
+                // out of room is silent. `fill = false` so a short read-out keeps a short dialog.
-                // dialog instead of stretching to the window.
                 Column(Modifier.weight(1f, fill = false).verticalScroll(rememberScrollState())) {
                     UsageBody(feed.snapshots)
                 }
@@ -93,8 +87,8 @@ private fun UsageBody(state: LoadState<List<UsageSnapshot>>) {
             is LoadState.Error -> Text(current.message, color = MaterialTheme.colorScheme.error)
             is LoadState.Loaded ->
                 if (current.value.isEmpty()) {
-                    // Not an error and not a blank screen: no machine offers a paid service,
+                    // Not an error and not a blank screen: no machine offers a paid service, so
-                    // so there is genuinely nothing to report and saying so is the answer.
+                    // there is genuinely nothing to report and saying so is the answer.
                     Text(
                         "No machine here runs anything with usage limits.",
                         style = MaterialTheme.typography.bodyMedium,
@@ -103,17 +97,16 @@ private fun UsageBody(state: LoadState<List<UsageSnapshot>>) {
                 } else {
                     // No card around each machine. A card is a step up the surface ladder, and
                     // inside a dialog -- itself a raised surface -- the step barely renders while
-                    // costing 16dp of padding on every side. What separates one machine from the
+                    // costing 16dp on every side. What separates one machine from the next is the
-                    // next is the line naming it, which is enough for a list this short.
+                    // line naming it.
                     current.value.forEachIndexed { index, snapshot ->
                         if (index > 0) {
                             Spacer(Modifier.height(20.dp))
                         }
-                        // Machine and service on one line: which account these numbers belong to
+                        // Machine and service on one line: which account these numbers belong to is
-                        // is decided by both together, and stacked as a heading over a subtitle
+                        // decided by both together, and stacked as a heading over a subtitle they
-                        // they read as a section of their own rather than as the label they are.
+                        // read as a section of their own. Small and quiet, because the numbers
-                        // Small and quiet, because the numbers below are what somebody opened
+                        // below are what somebody opened this to see.
-                        // this to see.
                         Text(
                             "${snapshot.setupName.ifEmpty { snapshot.setup }} · ${snapshot.provider}",
                             style = MaterialTheme.typography.bodySmall,
@@ -121,8 +114,8 @@ private fun UsageBody(state: LoadState<List<UsageSnapshot>>) {
                         )
                         SnapshotState(snapshot)
                         snapshot.windows.forEachIndexed { windowIndex, window ->
-                            // Between the bars, not after the last one: a trailing gap here is
+                            // Between the bars, not after the last one: a trailing gap here is what
-                            // what put a band of empty dialog above the Close button.
+                            // put a band of empty dialog above the Close button.
                             if (windowIndex > 0) {
                                 Spacer(Modifier.height(12.dp))
                             }
@@ -139,8 +132,7 @@ private fun UsageBody(state: LoadState<List<UsageSnapshot>>) {
  *
  * The distinction the old single message could not draw. A machine nobody has logged in on is
  * working exactly as somebody set it up, so it reads as a plain statement -- marking it would be
- * the interface nagging about a decision already made, and would dilute the marks that do mean
+ * the interface nagging about a decision already made. Only the two faults are coloured as faults.
- * something. Only the two faults are coloured as faults.
  */
 @Composable
 private fun SnapshotState(snapshot: UsageSnapshot) {
@@ -152,8 +144,8 @@ private fun SnapshotState(snapshot: UsageSnapshot) {
                 style = MaterialTheme.typography.bodyMedium,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )
-        // Reached but refused, versus never reached at all: different things to go and do,
+        // Reached but refused, versus never reached at all: different things to go and do, so they
-        // so they say different things rather than sharing one "unavailable".
+        // say different things rather than sharing one "unavailable".
         "failed" ->
             Text(
                 snapshot.detail ?: "Couldn't read the limits from this machine.",
@@ -200,10 +192,9 @@ private fun WindowBar(window: UsageWindow) {
 /**
  * "resets in 3h 12m" -- close enough for deciding whether to start a big task -- or nothing.
  *
- * Null for a window that is not running, which is the case this row has always drawn as nothing and
+ * Null for a window that is not running: there is no end to report. What this used to get wrong is
- * is right to: there is no end to report. What it used to get wrong is the other missing case, a
+ * the other missing case, a timestamp that arrived and could not be read -- printed raw, so a parse
- * timestamp that arrived and could not be read: that was printed raw, so a parse failure appeared
+ * failure appeared as an ISO string in a sentence written for a person. Both are named in
- * as an ISO string in the middle of a sentence written for a person. Both cases are named in
  * [WindowEnd], and the session bar words them the same way.
  */
 private fun resetLine(window: UsageWindow): String? =