diff --git a/AGENTS.md b/AGENTS.md
index a45b4bd..cdd7e0f 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -73,9 +73,18 @@ repo is in PLAN.md's "Backend layout" section.
   `EchoDriver`, and transcripts.
 - `app/` — Compose Android app, single `:androidApp` module, package
   `com.example.aiapp`, label "AI Sessions". `AppRoot.kt` is the navigation
-  `when`; `Api.kt`/`EventStream.kt` the REST + SSE clients; `Events.kt` the
-  event model mirror; `ServerConfig.kt` settings + Keystore-sealed token;
-  screens in `SessionListScreen/SessionScreen/SpawnScreen/SettingsScreen`.
+  `when`; `MainScreen.kt` the root's four tabs (sessions, import, models,
+  setups) with settings and refresh on the title row; `Api.kt`/`EventStream.kt`
+  the REST + SSE clients; `Events.kt` the event model mirror;
+  `ServerConfig.kt` settings + Keystore-sealed token; screens in
+  `SessionListScreen/SessionScreen/SpawnScreen/SettingsScreen`.
+  **Icons are Nerd Fonts glyphs from a committed subset**, not vector assets
+  and not ordinary Unicode — `NerdIcons.kt` declares each codepoint and
+  `app/build-icon-font.sh` subsets the font. The two lists have to agree: a
+  codepoint in the Kotlin that the script did not subset is a glyph that
+  silently isn't there. Rerun the script and commit its output when adding
+  one; it needs network access. `md-cog` and `md-refresh` are deliberately
+  the same codepoints dev-updater uses and must not drift from it.
 - `.dev-updater.ron` — what Dev Updater is asked to do with this checkout:
   the server (built in `server/`, run as `service: Managed(...)`) and the
   APK (built in `app/`), built in parallel. The project it serves is the
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt
index 7baa05d..a4c08a8 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt
@@ -16,37 +16,27 @@ import androidx.compose.ui.unit.dp
 import com.example.wgapplink.localNetworkAllowed
 
 /**
- * One `when` rather than a navigation library: four screens, with the list as the root and the back
- * button the only other way between them.
+ * 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
+ * of the same backend, none of them a step down from another -- and what is left in this `when` is
+ * only what genuinely is a step down: one session, spawning one, and settings.
  */
 private sealed class Screen {
-    data object SessionList : Screen()
+    data object Main : Screen()
 
     data class Session(val summary: SessionSummary) : Screen()
 
     data object Spawn : Screen()
 
-    /** Continuing a session the machine already had, rather than starting an empty one. */
-    data object Import : Screen()
-
     /**
-     * Reached from a session rather than from the list, because usage belongs to the provider
-     * running that session and not to the app. It carries the session back with it so Back returns
-     * where it came from -- see [Screen.Session].
-     */
-    data class Usage(val from: SessionSummary) : Screen()
-
-    /**
-     * What can be changed about one session. Carries the session back with it for the same reason
-     * [Screen.Usage] does, and carries it *out* renamed, so the session behind it shows the new
-     * name without waiting for a list refresh.
+     * What can be changed about one session. Carries the session back with it so Back returns where
+     * it came from, and carries it *out* renamed, so the session behind it shows the new name
+     * without waiting for a list refresh.
      */
     data class SessionSettings(val from: SessionSummary) : Screen()
 
-    data object Models : Screen()
-
-    data object Setups : Screen()
-
     data object Settings : Screen()
 }
 
@@ -58,7 +48,7 @@ private sealed class Screen {
 fun AppRoot(settingsVersion: Int) {
     val context = LocalContext.current
     var settings by remember(settingsVersion) { mutableStateOf(loadServerSettings(context)) }
-    var screen by remember { mutableStateOf<Screen>(Screen.SessionList) }
+    var screen by remember { mutableStateOf<Screen>(Screen.Main) }
     // Bumped whenever another screen changes something the list shows, so
     // returning to it refetches instead of showing a stale list.
     var reloadToken by remember { mutableIntStateOf(0) }
@@ -86,7 +76,7 @@ fun AppRoot(settingsVersion: Int) {
             existing = null,
             onSaved = { saved ->
                 settings = saved
-                screen = Screen.SessionList
+                screen = Screen.Main
             },
             onBack = null,
         )
@@ -97,32 +87,32 @@ fun AppRoot(settingsVersion: Int) {
     // reached by the system back gesture or a screen's own Back button.
     // Every leaf screen can have changed something the list shows, so it
     // always refetches.
-    val goToList = {
+    val goToMain = {
         reloadToken++
-        screen = Screen.SessionList
+        screen = Screen.Main
     }
-    if (screen !is Screen.SessionList) {
-        BackHandler(onBack = goToList)
+    if (screen !is Screen.Main) {
+        BackHandler(onBack = goToMain)
     }
 
     when (val here = screen) {
-        is Screen.SessionList ->
-            SessionListScreen(
+        is Screen.Main ->
+            MainScreen(
                 settings = current,
                 reloadToken = reloadToken,
                 onOpen = { screen = Screen.Session(it) },
                 onSpawn = { screen = Screen.Spawn },
-                onImport = { screen = Screen.Import },
-                onModels = { screen = Screen.Models },
-                onSetups = { screen = Screen.Setups },
+                onImported = { imported ->
+                    reloadToken++
+                    screen = Screen.Session(imported)
+                },
                 onSettings = { screen = Screen.Settings },
             )
         is Screen.Session ->
             SessionScreen(
                 settings = current,
                 summary = here.summary,
-                onBack = goToList,
-                onUsage = { screen = Screen.Usage(here.summary) },
+                onBack = goToMain,
                 onSettings = { screen = Screen.SessionSettings(here.summary) },
             )
         is Screen.Spawn ->
@@ -132,23 +122,7 @@ fun AppRoot(settingsVersion: Int) {
                     reloadToken++
                     screen = Screen.Session(spawned)
                 },
-                onBack = goToList,
-            )
-        is Screen.Import ->
-            ImportScreen(
-                settings = current,
-                onImported = { imported ->
-                    reloadToken++
-                    screen = Screen.Session(imported)
-                },
-                onBack = goToList,
-            )
-        is Screen.Usage ->
-            UsageScreen(
-                settings = current,
-                // Back to the session it was opened from, not to the list: this is a step down
-                // from that session, so stepping back is the one thing Back can mean here.
-                onBack = { screen = Screen.Session(here.from) },
+                onBack = goToMain,
             )
         is Screen.SessionSettings ->
             SessionSettingsScreen(
@@ -162,16 +136,14 @@ fun AppRoot(settingsVersion: Int) {
                 },
                 onBack = { screen = Screen.Session(here.from) },
             )
-        is Screen.Models -> ModelsScreen(settings = current, onBack = goToList)
-        is Screen.Setups -> SetupsScreen(settings = current, onBack = goToList)
         is Screen.Settings ->
             SettingsScreen(
                 existing = current,
                 onSaved = { saved ->
                     settings = saved
-                    goToList()
+                    goToMain()
                 },
-                onBack = goToList,
+                onBack = goToMain,
             )
     }
 }
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/Gear.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/Gear.kt
deleted file mode 100644
index 39a7b23..0000000
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/Gear.kt
+++ /dev/null
@@ -1,59 +0,0 @@
-package com.example.aiapp
-
-import androidx.compose.foundation.Canvas
-import androidx.compose.foundation.layout.size
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.runtime.Composable
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.geometry.Offset
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.StrokeCap
-import androidx.compose.ui.graphics.drawscope.Stroke
-import androidx.compose.ui.unit.dp
-import kotlin.math.PI
-import kotlin.math.cos
-import kotlin.math.sin
-
-/**
- * A gear: settings for the thing it sits beside.
- *
- * Drawn rather than set in a font, for the reason [Chevron] gives -- an icon glyph is one a system
- * font may not have, and whoever gets the empty box instead is never the person who wrote it. The
- * app has no icon set otherwise, and one dependency for one gear is a poor trade.
- *
- * A thick ring with eight blunt teeth cut into its edge. The proportions are the whole of whether
- * this reads as a gear: drawn first with thin teeth standing clear of a thin hub, it was a sun --
- * unmistakably, and only once it was looked at on a screen. What separates the two shapes is that a
- * gear's teeth are as heavy as its body and barely longer than they are wide, and that its centre
- * is a hole rather than a dot.
- *
- * It draws no label, so every caller owes it a `contentDescription`: that is all assistive
- * technology has, and it is also the answer to "what was that button for" six months from now.
- */
-@Composable
-fun Gear(modifier: Modifier = Modifier, colour: Color = MaterialTheme.colorScheme.primary) {
-    Canvas(modifier.size(20.dp)) {
-        val centre = Offset(size.width / 2, size.height / 2)
-        val tooth = 4.dp.toPx()
-        // The teeth end at the edge, so the body has to leave room for half a tooth's width
-        // where they meet the ring -- otherwise the widest part of the drawing is clipped.
-        val tip = size.minDimension / 2
-        val body = tip - tooth * 0.62f
-        drawCircle(colour, radius = body, centre, style = Stroke(3.dp.toPx()))
-        repeat(TEETH) { index ->
-            val angle = 2 * PI * index / TEETH
-            val direction = Offset(cos(angle).toFloat(), sin(angle).toFloat())
-            drawLine(
-                colour,
-                centre + direction * (body - 1.dp.toPx()),
-                centre + direction * tip,
-                strokeWidth = tooth,
-                // Square-ended, because a rounded tooth on a shape this small rounds away
-                // most of the tooth.
-                cap = StrokeCap.Butt,
-            )
-        }
-    }
-}
-
-private const val TEETH = 8
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/ImportScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/ImportScreen.kt
index 683ce5c..839c4bd 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/ImportScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/ImportScreen.kt
@@ -39,11 +39,7 @@ import kotlinx.coroutines.withContext
  * screen into a file reader.
  */
 @Composable
-fun ImportScreen(
-    settings: ServerSettings,
-    onImported: (SessionSummary) -> Unit,
-    onBack: () -> Unit,
-) {
+fun ImportScreen(settings: ServerSettings, reloadToken: Int, onImported: (SessionSummary) -> Unit) {
     val scope = rememberCoroutineScope()
     var setups by remember { mutableStateOf<LoadState<List<Setup>>>(LoadState.Loading) }
     var chosen by remember { mutableStateOf<Setup?>(null) }
@@ -73,7 +69,7 @@ fun ImportScreen(
         }
     }
 
-    LaunchedEffect(Unit) {
+    LaunchedEffect(reloadToken) {
         setups =
             try {
                 val found = withContext(Dispatchers.IO) { fetchSetups(settings) }
@@ -88,14 +84,8 @@ fun ImportScreen(
     }
 
     Column(Modifier.fillMaxSize().padding(16.dp)) {
-        Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
-            Text(
-                "Import a session",
-                style = MaterialTheme.typography.headlineSmall,
-                modifier = Modifier.weight(1f),
-            )
-            TextButton(onClick = onBack) { Text("Back") }
-        }
+        // No heading: the tab that selected this one already says "Import". The sentence below
+        // stays, because it says what importing *does*, which the tab label cannot.
         Text(
             "Sessions Claude Code already has on the machine. Importing continues one where it " +
                 "left off; the transcript here shows its recent history.",
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/MainScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/MainScreen.kt
new file mode 100644
index 0000000..76e0954
--- /dev/null
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/MainScreen.kt
@@ -0,0 +1,110 @@
+package com.example.aiapp
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.PrimaryTabRow
+import androidx.compose.material3.Tab
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+
+/**
+ * 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
+ * the same thing in less space and say one more thing besides: that these are places to be rather
+ * than errands to run. Sessions, the machine's importable history, the models on it and the
+ * machines themselves are all *the same backend*, looked at four ways, and none of them is a step
+ * 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"),
+    Import("Import"),
+    Models("Models"),
+    Setups("Setups"),
+}
+
+@Composable
+fun MainScreen(
+    settings: ServerSettings,
+    reloadToken: Int,
+    onOpen: (SessionSummary) -> Unit,
+    onSpawn: () -> Unit,
+    onImported: (SessionSummary) -> Unit,
+    onSettings: () -> Unit,
+) {
+    var tab by remember { mutableStateOf(MainTab.Sessions) }
+    var refreshToken by remember { mutableIntStateOf(0) }
+
+    // A tab the app put over the list has to step back to it rather than fall through to the
+    // system default, which closes the app -- that reads as a crash to somebody who only meant to
+    // 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()) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.fillMaxWidth().padding(start = 16.dp, end = 16.dp, top = 16.dp),
+        ) {
+            Text(
+                "AI Sessions",
+                style = MaterialTheme.typography.headlineSmall,
+                modifier = Modifier.weight(1f),
+            )
+            // 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
+            // screen -- everything below this row is one tab's business, and a control belongs
+            // with the thing it acts on.
+            Row(horizontalArrangement = Arrangement.spacedBy(GLYPH_BUTTON_GAP)) {
+                GlyphButton(REFRESH_GLYPH, "Refresh", { refreshToken++ })
+                GlyphButton(SETTINGS_GLYPH, "Settings", onSettings)
+            }
+        }
+        // Primary rather than the plain TabRow, which is deprecated in favour of the two that
+        // say where they sit: these are the app's top-level destinations.
+        PrimaryTabRow(selectedTabIndex = tab.ordinal) {
+            MainTab.entries.forEach { entry ->
+                Tab(
+                    selected = tab == entry,
+                    onClick = { tab = entry },
+                    text = { Text(entry.label) },
+                )
+            }
+        }
+
+        // Refreshing means "ask again about what I am looking at", so the button feeds the tab
+        // that is showing. The token from above means something else already changed what these
+        // show; the two are the same instruction to the tab below, so they are summed rather than
+        // tracked apart -- either one moving moves the sum, which is all a tab watches.
+        val token = reloadToken + refreshToken
+        when (tab) {
+            MainTab.Sessions ->
+                SessionListScreen(
+                    settings = settings,
+                    reloadToken = token,
+                    onOpen = onOpen,
+                    onSpawn = onSpawn,
+                )
+            MainTab.Import ->
+                ImportScreen(settings = settings, reloadToken = token, onImported = onImported)
+            MainTab.Models -> ModelsScreen(settings = settings, reloadToken = token)
+            MainTab.Setups -> SetupsScreen(settings = settings, reloadToken = token)
+        }
+    }
+}
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/ModelsScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/ModelsScreen.kt
index 263a09d..43e2816 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/ModelsScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/ModelsScreen.kt
@@ -40,7 +40,7 @@ import kotlinx.coroutines.withContext
  * going when this screen closes.
  */
 @Composable
-fun ModelsScreen(settings: ServerSettings, onBack: () -> Unit) {
+fun ModelsScreen(settings: ServerSettings, reloadToken: Int) {
     val scope = rememberCoroutineScope()
     var state by remember { mutableStateOf<LoadState<Models>>(LoadState.Loading) }
     var query by remember { mutableStateOf("") }
@@ -61,7 +61,10 @@ fun ModelsScreen(settings: ServerSettings, onBack: () -> Unit) {
     // Polled rather than pushed: a download belongs to the machine, not to
     // any session, so it has no event stream of its own. Slow enough not
     // to matter, frequent enough that a bar moves.
-    LaunchedEffect(Unit) {
+    // 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()
             delay(1500)
@@ -69,16 +72,6 @@ fun ModelsScreen(settings: ServerSettings, onBack: () -> Unit) {
     }
 
     Column(Modifier.fillMaxSize().padding(16.dp)) {
-        Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
-            Text(
-                "Models",
-                style = MaterialTheme.typography.headlineSmall,
-                modifier = Modifier.weight(1f),
-            )
-            TextButton(onClick = onBack) { Text("Back") }
-        }
-        Spacer(Modifier.height(8.dp))
-
         actionError?.let {
             Text(it, color = MaterialTheme.colorScheme.error)
             Spacer(Modifier.height(8.dp))
@@ -270,6 +263,10 @@ private fun DownloadCard(download: Download, onCancel: () -> Unit) {
             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
+                    // the opposite of what is happening.
+                    color = progressColor,
                     modifier = Modifier.fillMaxWidth(),
                 )
                 Text(
@@ -277,7 +274,7 @@ private fun DownloadCard(download: Download, onCancel: () -> Unit) {
                     style = MaterialTheme.typography.bodySmall,
                 )
             } else {
-                LinearProgressIndicator(Modifier.fillMaxWidth())
+                LinearProgressIndicator(color = progressColor, modifier = Modifier.fillMaxWidth())
                 Text(
                     "${gigabytes(download.done)} so far, total size unknown",
                     style = MaterialTheme.typography.bodySmall,
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/NerdIcons.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/NerdIcons.kt
new file mode 100644
index 0000000..3c21f2d
--- /dev/null
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/NerdIcons.kt
@@ -0,0 +1,134 @@
+package com.example.aiapp
+
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.font.Font
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+
+/**
+ * The icons the app draws, as glyphs in a Nerd Fonts subset rather than as vector assets.
+ *
+ * Drawing them as *text* is what makes them cheap: an icon beside a line of text wants that line's
+ * size, colour and baseline, and a `Text` gets all three for free where an `Icon` needs each one
+ * 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
+ * the person who wrote it. That objection is about *relying* on a system font, and it is exactly
+ * right: the answer is not to avoid glyphs but to ship them. The font here is
+ * `app/build-icon-font.sh`'s output -- five glyphs, 1.4 KB, subset out of the 3 MB symbols font and
+ * committed -- so the codepoints below are resolved by an asset in the APK and cannot come 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 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
+ * and something else in the other is the failure this is worth preventing. The script is copied
+ * rather than shared because most of what looks like duplication is the `GLYPHS` list, which has
+ * to 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))
+
+/** Nerd Fonts puts these in plane 15, so each is a surrogate pair. */
+private fun glyph(codePoint: Int) = String(Character.toChars(codePoint))
+
+/** `md-cog` -- settings for the thing it sits beside. */
+val SETTINGS_GLYPH = glyph(0xF0493)
+
+/** `md-refresh` -- ask the server again for whatever is on screen. */
+val REFRESH_GLYPH = glyph(0xF0450)
+
+/** `md-send` -- the filled paper plane: submit what is in the composer. */
+val SEND_GLYPH = glyph(0xF048A)
+
+/** `md-stop` -- a filled square: interrupt the turn that is running. */
+val STOP_GLYPH = glyph(0xF04DB)
+
+/** `md-arrow_left` -- back one level, to whatever this was opened from. */
+val BACK_GLYPH = glyph(0xF004D)
+
+/**
+ * `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
+ * what makes it read as a measurement rather than as a trend.
+ */
+val USAGE_GLYPH = glyph(0xF201)
+
+/**
+ * The size of a glyph button's box, which is the size of the glyph itself.
+ *
+ * Not the 48dp of a default `IconButton`: that box centres its drawing inside itself, so aligning
+ * the box against a title aligns nothing a reader can see, and the pressed-state ripple lands on
+ * the box rather than on the mark. A box that *is* the glyph aligns like any other content and
+ * takes its ripple with it. The cost is the touch target -- `minimumInteractiveComponentSize` is
+ * applied inside the caller's modifier, so a size set here wins over it.
+ */
+private val GLYPH_BUTTON_SIZE = 28.dp
+
+/**
+ * Restores the separation the 48dp boxes used to provide, now that the boxes are the size of what
+ * they draw: two of these plus the gap come to the same 48dp centre-to-centre spacing.
+ */
+val GLYPH_BUTTON_GAP = 48.dp - GLYPH_BUTTON_SIZE
+
+/**
+ * A glyph you can press: the icon equivalent of a `TextButton`.
+ *
+ * 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"
+ * 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
+ * or nobody checked.
+ */
+@Composable
+fun GlyphButton(
+    glyph: String,
+    label: String,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    enabled: Boolean = true,
+    colour: Color = MaterialTheme.colorScheme.primary,
+) {
+    IconButton(
+        onClick = onClick,
+        enabled = enabled,
+        modifier = modifier.size(GLYPH_BUTTON_SIZE).semantics { contentDescription = label },
+    ) {
+        Glyph(glyph, colour = if (enabled) colour else MaterialTheme.colorScheme.outline)
+    }
+}
+
+/**
+ * One icon, drawn as text.
+ *
+ * Callers that are already inside something pressable use this; [GlyphButton] is the one that adds
+ * the press. Either way the caller owes it a description, since neither draws a word.
+ */
+@Composable
+fun Glyph(
+    glyph: String,
+    modifier: Modifier = Modifier,
+    colour: Color = MaterialTheme.colorScheme.primary,
+    size: TextUnit = GLYPH_SIZE,
+) {
+    Text(glyph, fontFamily = NerdIcons, fontSize = size, color = colour, modifier = modifier)
+}
+
+/** The size an icon draws at beside a line of text. */
+private val GLYPH_SIZE = 20.sp
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionListScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionListScreen.kt
index de72668..8b1c383 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionListScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionListScreen.kt
@@ -39,8 +39,11 @@ import kotlinx.coroutines.withContext
 // as in dev-updater.
 
 /**
- * The session list -- the app's root screen. Sessions awaiting an answer sort to the top: that's
- * the "your turn" inbox.
+ * The sessions tab: sessions awaiting an answer sort to the top, which is the "your turn" inbox.
+ *
+ * No title and no Back of its own -- [MainScreen] owns the header and the tab that names this one.
+ * What stays here is the button that adds a session, because that acts on this list and nothing
+ * else.
  */
 @Composable
 fun SessionListScreen(
@@ -48,10 +51,6 @@ fun SessionListScreen(
     reloadToken: Int,
     onOpen: (SessionSummary) -> Unit,
     onSpawn: () -> Unit,
-    onImport: () -> Unit,
-    onModels: () -> Unit,
-    onSetups: () -> Unit,
-    onSettings: () -> Unit,
 ) {
     val scope = rememberCoroutineScope()
     var listState by remember { mutableStateOf<LoadState<List<SessionSummary>>>(LoadState.Loading) }
@@ -92,25 +91,6 @@ fun SessionListScreen(
 
     Box(Modifier.fillMaxSize()) {
         Column(Modifier.fillMaxSize().padding(16.dp)) {
-            // Title and actions on separate rows. Sharing one row worked
-            // with three actions and broke with the fourth: the title took
-            // whatever was left and wrapped "AI Sessions" onto three
-            // lines. Giving the actions their own row means adding a fifth
-            // costs nothing, and the title is never the thing that gives.
-            Text("AI Sessions", style = MaterialTheme.typography.headlineSmall)
-            Row(
-                verticalAlignment = Alignment.CenterVertically,
-                modifier = Modifier.fillMaxWidth(),
-            ) {
-                TextButton(onClick = onImport) { Text("Import") }
-                TextButton(onClick = onModels) { Text("Models") }
-                TextButton(onClick = onSetups) { Text("Setups") }
-                TextButton(onClick = onSettings) { Text("Settings") }
-                Spacer(Modifier.weight(1f))
-                TextButton(onClick = { refresh() }) { Text("Refresh") }
-            }
-            Spacer(Modifier.height(8.dp))
-
             when (val state = listState) {
                 is LoadState.Loading -> CircularProgressIndicator()
                 // The message as Api.kt wrote it, with nothing added: it is
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
index 0f5bda4..a4d0378 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
@@ -27,8 +27,8 @@ import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.LocalContentColor
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.OutlinedTextField
@@ -316,7 +316,6 @@ fun SessionScreen(
     settings: ServerSettings,
     summary: SessionSummary,
     onBack: () -> Unit,
-    onUsage: () -> Unit,
     onSettings: () -> Unit,
 ) {
     val scope = rememberCoroutineScope()
@@ -737,12 +736,18 @@ fun SessionScreen(
             }
         }
 
+    // One poll for this machine's limits, read by the two things that show them: the bar under
+    // the header, and the colour of the button that opens the dialog.
+    val usage = rememberSessionUsage(settings, summary.setup)
+    var usageOpen by remember { mutableStateOf(false) }
+
     Column(Modifier.fillMaxSize()) {
         Row(
             verticalAlignment = Alignment.CenterVertically,
             modifier = Modifier.fillMaxWidth().padding(horizontal = 8.dp, vertical = 4.dp),
         ) {
-            TextButton(onClick = onBack) { Text("Back") }
+            GlyphButton(BACK_GLYPH, "Back", onBack)
+            Spacer(Modifier.width(8.dp))
             Column(Modifier.weight(1f)) {
                 Text(title, style = MaterialTheme.typography.titleMedium)
                 Text(
@@ -766,22 +771,29 @@ fun SessionScreen(
             // the paid service's own numbers, so a session on a provider with no such service
             // gets an honest "unavailable" rather than a hidden button -- a control that comes
             // and goes makes its absence the signal, and absence cannot say why.
-            TextButton(onClick = onUsage) { Text("Usage") }
-            // A step down from this session, so it sits at the end of the session's own row.
-            // The name is the whole of what it holds today, which is why it is a gear and not a
-            // word: there will be more, and a bar of words has nowhere to put it.
-            IconButton(
-                onClick = onSettings,
-                modifier = Modifier.semantics { contentDescription = "Session settings" },
-            ) {
-                Gear()
+            // Coloured by the worst window behind it, so the row says whether the limits are
+            // worth opening before anybody opens them. Blue at every ordinary level and only
+            // yellow or red near a limit -- and the theme's plain control colour whenever there
+            // is no measurement, since blue is the low end of the scale here and would read as
+            // "checked, and fine" about a machine nobody could reach.
+            Row(horizontalArrangement = Arrangement.spacedBy(GLYPH_BUTTON_GAP)) {
+                GlyphButton(
+                    USAGE_GLYPH,
+                    "Usage",
+                    { usageOpen = true },
+                    colour = usageGlyphColour(usage),
+                )
+                // A step down from this session, so it sits at the end of the session's own row.
+                // The name is the whole of what it holds today, which is why it is a cog and not
+                // a word: there will be more, and a bar of words has nowhere to put it.
+                GlyphButton(SETTINGS_GLYPH, "Session settings", onSettings)
             }
         }
 
         // Under the header, above everything the session itself says: it is a fact about the
         // machine rather than a turn in the conversation, and it is the number that decides
         // whether to keep going -- which was a screen away from where that gets decided.
-        SessionUsageBar(settings = settings, setup = summary.setup)
+        SessionUsageBar(usage)
 
         (streamError ?: actionError)?.let { message ->
             Text(
@@ -1052,21 +1064,46 @@ fun SessionScreen(
                 }
                 if (running) {
                     OutlinedButton(onClick = { act { interruptSession(settings, summary.id) } }) {
-                        Text("Stop")
+                        // A filled square, which is what stop has looked like since tape decks.
+                        // Outlined beside the filled Send, so the pair still reads as one primary
+                        // action and one secondary -- the glyphs changed, the weighting did not.
+                        Glyph(
+                            STOP_GLYPH,
+                            colour = LocalContentColor.current,
+                            modifier = Modifier.semantics { contentDescription = "Stop" },
+                        )
                     }
                     Spacer(Modifier.width(8.dp))
                 }
-                // "Queue" while a turn is in flight, because that is what
-                // sending then does: the message is injected at the next
-                // tool boundary rather than starting a turn of its own.
-                // Naming it Send there would promise something immediate
-                // and describe something that waits.
-                Button(onClick = { send() }) { Text(if (running) "Queue" else "Send") }
+                // The paper plane alone when it means send. While a turn is in flight it keeps
+                // the word "Queue" beside it, because that is what sending then does -- the
+                // message is injected at the next tool boundary rather than starting a turn of
+                // its own -- and an icon that does two things while looking identical would
+                // promise something immediate and do something that waits. The word is also the
+                // button's accessible name, which is all a screen reader gets either way.
+                Button(onClick = { send() }) {
+                    Glyph(
+                        SEND_GLYPH,
+                        colour = LocalContentColor.current,
+                        modifier = Modifier.semantics { contentDescription = sendLabel(running) },
+                    )
+                    if (running) {
+                        Spacer(Modifier.width(8.dp))
+                        Text(sendLabel(running))
+                    }
+                }
             }
         }
     }
+
+    if (usageOpen) {
+        UsageDialog(settings = settings, onDismiss = { usageOpen = false })
+    }
 }
 
+/** What pressing Send does right now, said the same way to the eye and to a screen reader. */
+private fun sendLabel(running: Boolean) = if (running) "Queue" else "Send"
+
 /**
  * An inline transcript image, fetched (authenticated, pinned) from the session's files route. The
  * bitmap is remembered per ref, so scrolling doesn't refetch.
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionSettingsScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionSettingsScreen.kt
index 6117c18..20fe27d 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionSettingsScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionSettingsScreen.kt
@@ -7,6 +7,7 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.text.KeyboardActions
 import androidx.compose.foundation.text.KeyboardOptions
@@ -15,7 +16,6 @@ import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -77,12 +77,13 @@ fun SessionSettingsScreen(
 
     Column(Modifier.fillMaxSize().verticalScroll(rememberScrollState()).padding(16.dp)) {
         Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
+            GlyphButton(BACK_GLYPH, "Back", onBack)
+            Spacer(Modifier.width(8.dp))
             Text(
                 "Session settings",
                 style = MaterialTheme.typography.headlineSmall,
                 modifier = Modifier.weight(1f),
             )
-            TextButton(onClick = onBack) { Text("Back") }
         }
         Spacer(Modifier.height(16.dp))
 
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionUsageBar.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionUsageBar.kt
index fe75331..b14e389 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionUsageBar.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionUsageBar.kt
@@ -14,6 +14,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.dp
 import java.time.Duration
 import java.time.OffsetDateTime
@@ -21,12 +22,13 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.withContext
 
-/** How much of the five-hour window is gone, or why that isn't known. */
-sealed class FiveHourUsage {
+/** What one machine's rate limits came back as, or why they didn't. */
+sealed class SessionUsage {
     /** Nothing has come back yet. Distinct from every answer, including an empty one. */
-    data object Waiting : FiveHourUsage()
+    data object Waiting : SessionUsage()
 
-    data class Known(val percent: Double, val resetsAt: String?) : FiveHourUsage()
+    /** Every window the machine reported, in the order it reported them. */
+    data class Known(val windows: List<UsageWindow>) : SessionUsage()
 
     /**
      * This machine meters nothing, so there is no window to show.
@@ -37,7 +39,7 @@ sealed class FiveHourUsage {
      * snapshot for it -- and reading that silence as "couldn't find out" is exactly the mistake of
      * answering with the nearest available word. Drawn as nothing, because there is nothing.
      */
-    data object NotMetered : FiveHourUsage()
+    data object NotMetered : SessionUsage()
 
     /**
      * The question could not be answered, and why.
@@ -46,18 +48,66 @@ sealed class FiveHourUsage {
      * never share an appearance: a bar sitting at zero because a machine is unreachable reads as
      * plenty of headroom, which is the opposite of the truth.
      */
-    data class Unavailable(val why: String) : FiveHourUsage()
+    data class Unavailable(val why: String) : SessionUsage()
 }
 
 /** How often to ask again. The backend caches, so this re-reads its cache rather than the API. */
 private const val REFRESH_MS = 60_000L
 
+/**
+ * One machine's rate limits, polled.
+ *
+ * Hoisted out of [SessionUsageBar] because two things on a session's screen show this same answer
+ * -- the bar, and the colour of the button that opens the usage dialog. Fetching it twice would
+ * cost two round trips to say one thing, and the two copies would disagree for up to a minute at a
+ * time, which is the interface contradicting itself about a number somebody is deciding on.
+ */
+@Composable
+fun rememberSessionUsage(settings: ServerSettings, setup: String): SessionUsage {
+    var usage by remember(setup) { mutableStateOf<SessionUsage>(SessionUsage.Waiting) }
+    LaunchedEffect(setup) {
+        while (true) {
+            usage =
+                try {
+                    usageFor(withContext(Dispatchers.IO) { fetchUsage(settings) }, setup)
+                } catch (e: ApiException) {
+                    SessionUsage.Unavailable(e.message ?: "couldn't reach the backend")
+                }
+            delay(REFRESH_MS)
+        }
+    }
+    return usage
+}
+
+/**
+ * The colour for a control that reports on [usage] as a whole: the worst window's.
+ *
+ * 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
+ * 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
+ * the button is where those say, in words, which one they are.
+ */
+@Composable
+fun usageGlyphColour(usage: SessionUsage): Color =
+    when (usage) {
+        is SessionUsage.Known ->
+            usage.windows.maxOfOrNull { it.percent }?.let { quotaColor(it) }
+                ?: MaterialTheme.colorScheme.primary
+        else -> MaterialTheme.colorScheme.primary
+    }
+
 /**
  * The five-hour window for the machine this session runs on, under the session's own header.
  *
- * Here rather than only on the usage screen because it is the number that decides whether to keep
+ * Here rather than only in the usage dialog because it is the number that decides whether to keep
  * going, and it was a screen away from the place that decision gets made. It reports on this
- * session's machine alone -- the usage screen is still where every machine is compared.
+ * 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
  * account. It is never derived from what this app has watched go past: the transcript's token
@@ -65,31 +115,22 @@ private const val REFRESH_MS = 60_000L
  * out of them would be a guess wearing a measurement's clothes.
  */
 @Composable
-fun SessionUsageBar(settings: ServerSettings, setup: String, modifier: Modifier = Modifier) {
-    var usage by remember(setup) { mutableStateOf<FiveHourUsage>(FiveHourUsage.Waiting) }
-    // The countdown moves even when the numbers do not, so it is driven by a clock this loop
-    // advances 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 ticks when the quota
-    // happens to move would sit at a stale figure for hours.
+fun SessionUsageBar(usage: SessionUsage, modifier: Modifier = Modifier) {
+    // 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
+    // happened to move would sit at a stale figure for hours.
     var now by remember { mutableStateOf(OffsetDateTime.now()) }
-
-    LaunchedEffect(setup) {
+    LaunchedEffect(Unit) {
         while (true) {
-            usage =
-                try {
-                    val snapshots = withContext(Dispatchers.IO) { fetchUsage(settings) }
-                    fiveHourFor(snapshots, setup)
-                } catch (e: ApiException) {
-                    FiveHourUsage.Unavailable(e.message ?: "couldn't reach the backend")
-                }
-            now = OffsetDateTime.now()
             delay(REFRESH_MS)
+            now = OffsetDateTime.now()
         }
     }
 
     // Nothing at all for a machine that meters nothing: a row saying "unknown" there would
     // report a problem about a setup somebody chose, on every screen, forever.
-    if (usage is FiveHourUsage.NotMetered) {
+    if (usage is SessionUsage.NotMetered) {
         return
     }
 
@@ -97,39 +138,47 @@ fun SessionUsageBar(settings: ServerSettings, setup: String, modifier: Modifier
         verticalAlignment = Alignment.CenterVertically,
         modifier = modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 2.dp),
     ) {
+        // Words, not a colour and not an empty bar: every one of these is a different kind of
+        // answer from "this much is used", and only words carry a difference in kind.
         when (val state = usage) {
-            FiveHourUsage.NotMetered -> Unit
-            // Words, not a colour and not an empty bar: "couldn't check" is a different kind of
-            // answer from "this much is used", and only words carry a difference in kind.
-            is FiveHourUsage.Unavailable ->
-                Text(
-                    "5-hour usage unknown -- ${state.why}",
-                    style = MaterialTheme.typography.labelSmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                )
-            FiveHourUsage.Waiting ->
-                Text(
-                    "5-hour usage: checking",
-                    style = MaterialTheme.typography.labelSmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                )
-            is FiveHourUsage.Known -> {
-                LinearProgressIndicator(
-                    progress = { (state.percent / 100.0).toFloat().coerceIn(0f, 1f) },
-                    color = usageColor,
-                    modifier = Modifier.weight(1f),
-                )
-                Text(
-                    fiveHourLabel(state, now),
-                    style = MaterialTheme.typography.labelSmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    modifier = Modifier.padding(start = 8.dp),
-                )
+            SessionUsage.NotMetered -> Unit
+            is SessionUsage.Unavailable -> UsageNote("5-hour usage unknown -- ${state.why}")
+            SessionUsage.Waiting -> UsageNote("5-hour usage: checking")
+            is SessionUsage.Known -> {
+                val window = state.windows.firstOrNull { it.kind == "session" }
+                if (window == null) {
+                    UsageNote("5-hour usage unknown -- no five-hour window reported")
+                } else {
+                    LinearProgressIndicator(
+                        progress = { (window.percent / 100.0).toFloat().coerceIn(0f, 1f) },
+                        // The same step at the same percentages as the dialog's bars: this is the
+                        // same measurement, and a reader who learned the colour there has to be
+                        // able to read it here without checking which screen they are on.
+                        color = quotaColor(window.percent),
+                        modifier = Modifier.weight(1f),
+                    )
+                    Text(
+                        fiveHourLabel(window, now),
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.padding(start = 8.dp),
+                    )
+                }
             }
         }
     }
 }
 
+/** Anything this row says instead of drawing a bar, so all of them look the same. */
+@Composable
+private fun UsageNote(text: String) {
+    Text(
+        text,
+        style = MaterialTheme.typography.labelSmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+    )
+}
+
 /**
  * "42% -- 2h 15m left": how much is gone, then how long what is left has to last.
  *
@@ -140,43 +189,32 @@ fun SessionUsageBar(settings: ServerSettings, setup: String, modifier: Modifier
  * no reset time, and saying "refresh soon" there would put a recommendation on the screen that
  * nothing measured. The percentage is still known, so it is still shown.
  */
-private fun fiveHourLabel(state: FiveHourUsage.Known, now: OffsetDateTime): String {
-    val percent = "${state.percent.toInt()}%"
-    val until = state.resetsAt?.let { remainingUntil(it, now) }
+private fun fiveHourLabel(window: UsageWindow, now: OffsetDateTime): String {
+    val percent = "${window.percent.toInt()}%"
+    val until = window.resetsAt?.let { remainingUntil(it, now) }
     return when {
-        until == null -> "$percent \u00b7 reset time unknown"
+        until == null -> "$percent · reset time unknown"
         // Under a minute, including past the end: the number would round to "0m left", which reads
         // as a measurement rather than as the window having run out.
-        until < Duration.ofMinutes(1) -> "$percent \u00b7 refresh soon"
-        else -> "$percent \u00b7 ${formatSpan(until)} left"
+        until < Duration.ofMinutes(1) -> "$percent · refresh soon"
+        else -> "$percent · ${formatSpan(until)} left"
     }
 }
 
 /**
- * The five-hour window for one machine, out of every machine's snapshot.
+ * One machine's snapshot, out of every machine's.
  *
- * Selects the window by `kind`, which is the API's own word, rather than by the label beside it --
- * the label is written to be read and would stop matching the day its wording changes, silently
- * leaving the bar with nothing to show.
- *
- * Every way of having *failed* to get a number is [FiveHourUsage.Unavailable] with the reason in
- * it: a machine nobody logged into, one that could not be reached, a snapshot that came back
- * without the window. None of them may look like zero, and none of them may look like
- * [FiveHourUsage.NotMetered], which is the machine having no quota rather than the question going
- * unanswered.
+ * 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.
  */
-fun fiveHourFor(snapshots: List<UsageSnapshot>, setup: String): FiveHourUsage {
-    val mine = snapshots.firstOrNull { it.setup == setup }
+fun usageFor(snapshots: List<UsageSnapshot>, setup: String): SessionUsage {
     // No snapshot at all means the backend never asked, which it only does for a machine with
     // nothing metered on it. That is a different answer from having asked and failed.
-    if (mine == null) {
-        return FiveHourUsage.NotMetered
-    }
+    val mine = snapshots.firstOrNull { it.setup == setup } ?: return SessionUsage.NotMetered
     if (mine.state != "ok") {
-        return FiveHourUsage.Unavailable(mine.detail ?: mine.state)
+        return SessionUsage.Unavailable(mine.detail ?: mine.state)
     }
-    val window =
-        mine.windows.firstOrNull { it.kind == "session" }
-            ?: return FiveHourUsage.Unavailable("no five-hour window reported")
-    return FiveHourUsage.Known(window.percent, window.resetsAt)
+    return SessionUsage.Known(mine.windows)
 }
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt
index b733ca1..3714478 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt
@@ -11,12 +11,12 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
 import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -79,14 +79,21 @@ fun SettingsScreen(
 
     Column(Modifier.fillMaxSize().padding(16.dp)) {
         Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
+            // Leading, where a back arrow points at what it returns to. Trailing it would put a
+            // 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
+            // a capability being withheld but a promise it could not keep.
+            if (onBack != null) {
+                GlyphButton(BACK_GLYPH, "Back", onBack)
+                Spacer(Modifier.width(8.dp))
+            }
             Text(
                 "Server",
                 style = MaterialTheme.typography.headlineSmall,
                 modifier = Modifier.weight(1f),
             )
-            if (onBack != null) {
-                TextButton(onClick = onBack) { Text("Back") }
-            }
         }
         Spacer(Modifier.height(8.dp))
         Text(
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SetupsScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SetupsScreen.kt
index 7aad7d8..c85da27 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SetupsScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SetupsScreen.kt
@@ -38,7 +38,7 @@ import kotlinx.coroutines.withContext
  * which is what keeps the enrolled token from being able to introduce commands.
  */
 @Composable
-fun SetupsScreen(settings: ServerSettings, onBack: () -> Unit) {
+fun SetupsScreen(settings: ServerSettings, reloadToken: Int) {
     val scope = rememberCoroutineScope()
     var state by remember { mutableStateOf<LoadState<List<Setup>>>(LoadState.Loading) }
     var adding by remember { mutableStateOf(false) }
@@ -56,14 +56,13 @@ fun SetupsScreen(settings: ServerSettings, onBack: () -> Unit) {
             }
     }
 
-    LaunchedEffect(Unit) { reload() }
+    LaunchedEffect(reloadToken) { reload() }
 
     Column(Modifier.fillMaxSize().padding(16.dp)) {
-        Text("Setups", style = MaterialTheme.typography.headlineSmall)
+        // The heading and Back are the tab row's now; adding a machine is this tab's own work
+        // and stays with the list it adds to.
         Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
             TextButton(onClick = { adding = true }) { Text("Add machine") }
-            Spacer(Modifier.weight(1f))
-            TextButton(onClick = onBack) { Text("Back") }
         }
         Spacer(Modifier.height(8.dp))
 
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/Theme.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/Theme.kt
index e59a2c7..0846b30 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/Theme.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/Theme.kt
@@ -130,16 +130,43 @@ val warningColor: Color
     @Composable get() = Mocha.Yellow
 
 /**
- * How much of a quota window is gone, on the bar under a session's header.
+ * The fill of a progress bar that is only reporting how far along something is.
  *
- * Blue because that bar reports a quantity rather than a verdict: it sits on a screen the reader
- * opened to do something else, and the scheme's primary made it the loudest thing there. The usage
- * screen is where the same number turns [warningColor] and then [overLimitColor] -- somebody
- * looking at that screen came to be told where the limits are.
+ * 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
+ * compaction, has no limit to be near: it finishes. Only a bar measuring a *quota* escalates, and
+ * that one is [quotaColor].
  */
-val usageColor: Color
+val progressColor: Color
     @Composable get() = Mocha.Blue
 
+/**
+ * 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
+ * colouring by consequence is that the reader learns the step once -- two bars showing the same 80%
+ * in different colours teaches nothing except that the colour cannot be trusted. It reads as a
+ * difference in degree, which is all colour can carry: the states that differ in *kind* from this
+ * -- 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.
+ */
+@Composable
+fun quotaColor(percent: Double): Color =
+    when {
+        percent >= OVER_LIMIT_PERCENT -> overLimitColor
+        percent >= WARNING_PERCENT -> warningColor
+        else -> progressColor
+    }
+
+/** Close enough to the limit to be worth seeing before starting something big. */
+private const val WARNING_PERCENT = 75.0
+
+/** Close enough that the next turn may be the one that is refused. */
+private const val OVER_LIMIT_PERCENT = 95.0
+
 /**
  * Code: a fenced block, an inline span, a tool's input.
  *
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/UsageScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/UsageDialog.kt
similarity index 74%
rename from app/androidApp/src/main/kotlin/com/example/aiapp/UsageScreen.kt
rename to app/androidApp/src/main/kotlin/com/example/aiapp/UsageDialog.kt
index 682f89c..74daf3e 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/UsageScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/UsageDialog.kt
@@ -3,12 +3,12 @@ package com.example.aiapp
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Card
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.LinearProgressIndicator
@@ -30,9 +30,18 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 
-/** Window bars for the account's rate limits, with reset times. */
+/**
+ * Window bars for the account's rate limits, with reset times.
+ *
+ * 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
+ * this away", which is what dismissing does. The system back gesture dismisses it, since a `Dialog`
+ * handles that itself.
+ */
 @Composable
-fun UsageScreen(settings: ServerSettings, onBack: () -> Unit) {
+fun UsageDialog(settings: ServerSettings, onDismiss: () -> Unit) {
     val scope = rememberCoroutineScope()
     var state by remember { mutableStateOf<LoadState<List<UsageSnapshot>>>(LoadState.Loading) }
 
@@ -49,24 +58,35 @@ fun UsageScreen(settings: ServerSettings, onBack: () -> Unit) {
     }
     LaunchedEffect(Unit) { refresh() }
 
-    Column(Modifier.fillMaxSize().verticalScroll(rememberScrollState()).padding(16.dp)) {
-        Row(verticalAlignment = Alignment.CenterVertically, 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 paid service
-            // answered there -- naming the session's provider here made an echo session's
-            // screen read "echo" above a card reading "claude", which is a claim about echo
-            // that nothing measured. Each card names the machine and the service it came from,
-            // which is the true scope.
-            Text(
-                "Usage",
-                style = MaterialTheme.typography.headlineSmall,
-                modifier = Modifier.weight(1f),
-            )
-            TextButton(onClick = onBack) { Text("Back") }
-            TextButton(onClick = { refresh() }) { Text("Refresh") }
-        }
-        Spacer(Modifier.height(16.dp))
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                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
+                // paid service answered there -- naming the session's provider here made an echo
+                // session's screen read "echo" above a card reading "claude", which is a claim
+                // about echo that nothing measured. Each card names the machine and the service
+                // it came from, which is the true scope.
+                Text("Usage", modifier = Modifier.weight(1f))
+                GlyphButton(REFRESH_GLYPH, "Refresh usage", { refresh() })
+            }
+        },
+        // Scrolls here rather than being trimmed: a machine can report any number of windows and
+        // there can be any number of machines, and a dialog is the one place where running out of
+        // room is silent.
+        text = { Column(Modifier.verticalScroll(rememberScrollState())) { UsageBody(state) } },
+        confirmButton = { TextButton(onClick = onDismiss) { Text("Close") } },
+    )
+}
 
+/** What came back, or why nothing did. Split out so the dialog above reads as its own shape. */
+@Composable
+private fun UsageBody(state: LoadState<List<UsageSnapshot>>) {
+    Column {
         when (val current = state) {
             is LoadState.Loading -> CircularProgressIndicator()
             is LoadState.Error -> Text(current.message, color = MaterialTheme.colorScheme.error)
@@ -146,12 +166,6 @@ private fun SnapshotState(snapshot: UsageSnapshot) {
 
 @Composable
 private fun WindowBar(window: UsageWindow) {
-    val color =
-        when {
-            window.percent >= 95 -> overLimitColor
-            window.percent >= 75 -> warningColor
-            else -> MaterialTheme.colorScheme.primary
-        }
     Column {
         Row(modifier = Modifier.fillMaxWidth()) {
             Text(
@@ -164,7 +178,7 @@ private fun WindowBar(window: UsageWindow) {
         Spacer(Modifier.height(4.dp))
         LinearProgressIndicator(
             progress = { (window.percent / 100.0).toFloat().coerceIn(0f, 1f) },
-            color = color,
+            color = quotaColor(window.percent),
             modifier = Modifier.fillMaxWidth(),
         )
         window.resetsAt?.let {
diff --git a/app/androidApp/src/main/res/font/nerd_icons.ttf b/app/androidApp/src/main/res/font/nerd_icons.ttf
new file mode 100644
index 0000000..c3708c7
Binary files /dev/null and b/app/androidApp/src/main/res/font/nerd_icons.ttf differ
diff --git a/app/build-icon-font.sh b/app/build-icon-font.sh
new file mode 100755
index 0000000..964315f
--- /dev/null
+++ b/app/build-icon-font.sh
@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+# Rebuilds androidApp/src/main/res/font/nerd_icons.ttf.
+#
+# The app draws a handful of icons -- a cog, a refresh arrow, send, stop --
+# as text in a Nerd Fonts glyph rather than as vector assets or as ordinary
+# Unicode. Unicode has no character for most of these, and the ones it does
+# have are not reliably in an Android system font, so they land as tofu
+# boxes on somebody's phone. Shipping the subset removes the hope: the
+# glyph is in the APK.
+#
+# The whole symbols font is 3 MB for the handful below, so what is
+# committed is a subset. Add a codepoint to GLYPHS below and to NerdIcons.kt
+# (the two lists have to agree -- a codepoint in the Kotlin but not here is
+# a glyph that silently doesn't exist), then run this and commit the result.
+#
+# Needs python3 and network access; fontTools is fetched into a temporary
+# venv, so nothing has to be installed on the machine.
+#
+# Copied from dev-updater's script of the same name rather than shared
+# through wg-app-link, for the reason Theme.kt gives about the palette: the
+# link is the tunnel, the pinned CA and enrollment, and an icon set is a
+# preference rather than part of that contract.
+set -euo pipefail
+
+# Codepoint, then the Nerd Fonts glyph name it came from. Material Design
+# Icons bar one, so they read as one family -- and the first two are
+# deliberately the same two dev-updater uses, since a cog and a refresh
+# arrow mean the same thing in both apps. The exception is noted on its
+# own line, as dev-updater's script does with its two.
+GLYPHS=(
+    U+F0493  # md-cog
+    U+F0450  # md-refresh
+    U+F048A  # md-send
+    U+F04DB  # md-stop
+    U+F004D  # md-arrow_left
+    U+F201   # fa-line_chart -- Font Awesome's, asked for by name
+)
+
+url=https://github.com/ryanoasis/nerd-fonts/releases/latest/download/NerdFontsSymbolsOnly.zip
+out="$(cd "$(dirname "$0")" && pwd)/androidApp/src/main/res/font/nerd_icons.ttf"
+work="$(mktemp -d)"
+trap 'rm -rf "$work"' EXIT
+
+echo "Fetching $url"
+curl -fsSL -o "$work/nf.zip" "$url"
+python3 -c 'import sys,zipfile; zipfile.ZipFile(sys.argv[1]).extractall(sys.argv[2])' "$work/nf.zip" "$work"
+
+python3 -m venv "$work/venv"
+"$work/venv/bin/pip" -q install fonttools
+
+unicodes="$(IFS=,; echo "${GLYPHS[*]}")"
+mkdir -p "$(dirname "$out")"
+# The proportional face rather than the Mono one: these are drawn inline
+# beside text, where a fixed advance would pad each icon out to a cell.
+"$work/venv/bin/pyftsubset" "$work/SymbolsNerdFont-Regular.ttf" \
+    --unicodes="$unicodes" \
+    --layout-features= \
+    --drop-tables+=DSIG \
+    --output-file="$out"
+
+echo "Wrote $out ($(stat -c %s "$out") bytes) with ${#GLYPHS[@]} glyphs"