Ask a provider for its models, and let the app update its CLI

The Claude model list was four words in machines.rs, copied into every
machine's config.ron at discovery -- so a model the CLI had gained was
unreachable from the phone, which is how Opus 5.5 came to be invisible.
Every catalog is now read from the provider itself when a picker opens:
Claude Code over its control channel (control_request{subtype:list_models},
the same channel the driver sends set_model down, since the CLI has no
listing command), Codex over app-server, llama.cpp from the GGUFs on its
machine. Echo is the one case config.ron still answers, having nothing to
ask. A row the CLI marks disabled -- a model the installed version is too
old to run -- is dropped rather than offered as a chip that fails.

The reading of each catalog lives in that driver's own module, and
provider_models is one line per driver: core code says which driver to ask
and never what an answer looks like. parse_codex_models moved out for the
same reason.

Beside it, a provider now reports the version of its program and can be
told to update it. The version comes from --version on its own machine,
read from whichever stream carried it but only from a run that exited 0 --
llama-server prints its version to stderr, and so does "command not found".
It is never compared against a latest release, which nothing here can know.
Update runs the driver's own updater, or an updateCommand the config file
names for an install those will not touch; its whole output comes back,
because every install on these machines is package-managed and the
updater's refusal is the sentence worth reading. Nothing on its stdin, so a
password prompt fails rather than hangs.

A catalog that cannot be read no longer fails the whole provider view: that
is exactly the provider somebody came there to update, and refusing the
screen took the version and the Update button away with it.

Verified against a scratch server and on the emulator: the live catalog
(1.06s, disabled row absent), all four providers' versions including the
unknown state, the confirmation and output dialogs, a configured command
returning in 87ms with its stdin closed, and Update correctly disabled for
llama.cpp.

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

AGENTS.md

@@ -175,6 +175,29 @@ Module-by-module intent is in PLAN.md's "Backend layout".
   `wc -c` of the partial against the size HuggingFace published, the sha256
   it publishes is what makes a resume safe, and a finished download is not a
   state: it is a model, in the list beside the one still going.
+  **A provider's models are asked for at the moment a picker opens**
+  (2026-09-23, `machines::provider_models`): Claude Code over its control
+  channel (`control_request{subtype:list_models}`, the same channel the driver
+  sends `set_model` down -- the CLI has no listing command), Codex over
+  app-server, llama.cpp from the GGUFs on its machine. The list used to be four
+  words in `machines.rs` baked into `config.ron` at discovery, so a model the
+  CLI gained was unreachable from the phone. Two things fall out of it and are
+  easy to get wrong again -- **the reading of a catalog lives in its driver's
+  module** and `provider_models` is a line per driver, because core code knowing
+  what a Claude answer looks like is the session-type branch this project does
+  not have; and a row the CLI marks `disabled` is dropped, being a model the
+  installed version is too old to run.
+  **A provider reports its version and can be told to update itself**
+  (2026-09-23, `machines::provider_version` / `update_provider`, drawn in
+  `ProviderScreen.kt`). The version is `--version` on that machine, taken from
+  whichever stream carried it but **only from a run that exited 0** -- "command
+  not found" is on stderr too. It is never compared against a latest release,
+  which nothing here can know. Update runs `DriverKind::update_args` (`claude
+  update`, `codex update`) or the `updateCommand` a provider's config entry
+  names, which is config-file only and deliberately not on any route; its whole
+  output comes back, because every install on these machines is package-managed
+  and the updater's refusal is the sentence worth reading. Nothing on its stdin,
+  so a password prompt fails rather than hangs.
   Codex is one persistent `codex app-server --stdio` process per session; its
   driver uses native turn steering and interruption, persists the protocol
   state and thread id, and reads subscription limits through the same CLI

PLAN.md

@@ -85,6 +85,39 @@ a control that silently did nothing).
   should keep being served by the ordinary build. A provider of its own is
   what that has to be, because a router process, its preset file and a
   model's load settings all hang off the provider.
+- **A provider's model catalog is asked for, never written down** (2026-09-23).
+  `GET /machines/{id}/providers/{p}/models` puts the question to the provider
+  itself at the moment a picker opens: Claude Code over its control channel
+  (`control_request{subtype:list_models}`), Codex over app-server
+  (`model/list`), llama.cpp by listing the GGUFs on that machine's disk. Echo
+  is the one case the config file answers, because there is nothing to ask.
+  Until this the Claude list was four words in `machines.rs` copied into every
+  machine's `config.ron` at discovery, so a model the CLI had gained was
+  unreachable from the phone and one it had lost was still offered — Opus 5.5
+  is what found it. **What decides which models exist is the installed CLI and
+  the account**, neither of which this app is a party to, so anything it
+  remembers about them is a guess going stale. Rows the CLI marks `disabled`
+  (a model the installed version is too old to run) are dropped rather than
+  offered, since choosing one is a session that fails at the spawn. The dispatch
+  is a line per driver in `machines::provider_models` and the reading of each
+  catalog lives in that driver's own module — core code knows which driver to
+  ask, never what an answer looks like.
+- **A provider says which version it is, and can be told to update** (2026-09-23).
+  The provider view reports `<program> --version` from the machine it runs on,
+  as `known` or `unknown` with the reason: the version is read from whichever of
+  stdout and stderr carried it, but **only from a run that succeeded**, because
+  "command not found" is also written to stderr and must never be drawn where a
+  version goes. It is never compared against a latest release — what the latest
+  is cannot be known from here, and "up to date" would be a claim nobody
+  checked. Update runs the driver's own updater (`claude update`, `codex
+  update`), or an `updateCommand` the config file names for an install those
+  will not touch — config-file only, never a route, so the phone still names no
+  command. The updater's **whole output** is what comes back rather than a
+  verdict read out of it: every install on these two machines is package-managed,
+  and "Claude is managed by a package manager" is the sentence somebody needs.
+  It runs with nothing on its stdin, so a command that stops to ask for a
+  password fails instead of waiting for ever, with a ten-minute backstop for one
+  that waits on something else.
 - **Migration code is deleted once the update carrying it is received.** The
   providers/hosts migration ran on the one host there is and is gone. A file
   in the old shape now fails to parse, which is correct because no such file

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

@@ -1713,8 +1713,22 @@ data class ProviderView(
     val command: String?,
     /** What each of this provider's models takes; empty for one that loads no models. */
     val modelParams: List<ParamSpec>,
+    /**
+     * Which version of its program is installed, or why that could not be asked; null for a kind
+     * with no program of its own. Never a claim about whether it is the latest — the server does
+     * not know what the latest is, and neither does this.
+     */
+    val version: ProviderVersion?,
+    /** Whether anything the backend has can update it. The control is drawn either way. */
+    val updatable: Boolean,
     val maxLoaded: Int?,
     val models: List<ProviderModel>,
+    /**
+     * Why the catalog could not be read, where it could not be. Carried rather than failing the
+     * whole screen: a provider whose program cannot be asked is the one somebody came here to
+     * update, and refusing the screen takes the Update button away with it.
+     */
+    val modelsError: String?,
     val mcpServers: List<String>,
     val server: ServerState?,
 )
@@ -1732,6 +1746,26 @@ data class ProviderModel(
     val status: String?,
 )
 
+/**
+ * A provider's installed version, or the reason there isn't one to show.
+ *
+ * Two cases rather than a nullable string, because "the machine could not be reached" and "it is
+ * version 2.1.281" are different things to draw and an absent string is both.
+ */
+sealed interface ProviderVersion {
+    data class Known(val text: String) : ProviderVersion
+
+    data class Unknown(val why: String) : ProviderVersion
+}
+
+/**
+ * What an update said.
+ *
+ * Its output alone: the version afterwards comes from refetching the provider, which the screen
+ * does anyway once the action finishes, rather than from a second answer that could disagree.
+ */
+data class UpdateResult(val said: String)
+
 /** The shared server behind a provider: whether it is up, and where the backend reaches it. */
 data class ServerState(val running: Boolean, val port: Int?)
 
@@ -1747,6 +1781,8 @@ fun fetchProvider(settings: ServerSettings, machineId: String, provider: String)
             kind = body.getString("kind"),
             command = body.optString("command").ifEmpty { null },
             modelParams = body.optJSONArray("modelParams")?.mapObjects(::parseParamSpec).orEmpty(),
+            version = parseProviderVersion(body.optJSONObject("version")),
+            updatable = body.optBoolean("updatable", false),
             maxLoaded = if (body.isNull("maxLoaded")) null else body.optInt("maxLoaded"),
             models =
                 body
@@ -1760,6 +1796,7 @@ fun fetchProvider(settings: ServerSettings, machineId: String, provider: String)
                         )
                     }
                     .orEmpty(),
+            modelsError = body.optString("modelsError").ifEmpty { null },
             mcpServers = body.optJSONArray("mcpServers")?.strings().orEmpty(),
             server =
                 body.optJSONObject("server")?.let { server ->
@@ -1771,6 +1808,33 @@ fun fetchProvider(settings: ServerSettings, machineId: String, provider: String)
         )
     }
 
+private fun parseProviderVersion(body: JSONObject?): ProviderVersion? {
+    val text = body?.optString("text").orEmpty()
+    return when (body?.optString("state")) {
+        "known" -> ProviderVersion.Known(text)
+        // An unreadable state is not a version. Saying so is the honest answer; making one up from
+        // the text beside it would put a sentence where a version number goes.
+        "unknown" -> ProviderVersion.Unknown(text)
+        else -> null
+    }
+}
+
+/**
+ * Updates the program one provider runs, on the machine it runs on.
+ *
+ * Long, because the work is a download of a couple of hundred megabytes onto a machine that may be
+ * at the far end of the tunnel. The backend stops it well before this does.
+ */
+fun updateProvider(settings: ServerSettings, machineId: String, provider: String): UpdateResult =
+    requestFromServer(
+        settings,
+        providerPath(machineId, provider, "/update"),
+        method = "POST",
+        readTimeoutMs = 660000,
+    ) {
+        UpdateResult(said = it.jsonObject().optString("said"))
+    }
+
 /** How many models this provider's server keeps loaded at once; null for the default. */
 fun setProviderSettings(
     settings: ServerSettings,

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

@@ -1,6 +1,7 @@
 package com.example.aiapp
 
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -73,6 +74,10 @@ fun ProviderScreen(
     var busy by remember { mutableStateOf<String?>(null) }
     var actionError by remember { mutableStateOf<String?>(null) }
     var confirmingDelete by remember { mutableStateOf<ProviderModel?>(null) }
+    var confirmingUpdate by remember { mutableStateOf(false) }
+    // What the updater said, kept until it is read: it is the whole point of pressing the button —
+    // an updater that declines names what to do instead — and there is nowhere else to see it.
+    var updateSaid by remember { mutableStateOf<String?>(null) }
 
     // The machine's own models and what is being fetched onto it. Only for a provider that serves
     // files off that machine's disk -- everything else names its models rather than holding them,
@@ -142,6 +147,34 @@ fun ProviderScreen(
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                     )
                 }
+                // Under the program it is the version of, and above the control that changes it:
+                // the provider's own binary, as opposed to everything below, which is models. A
+                // kind with no program to ask draws neither.
+                view.version?.let { version ->
+                    Text(
+                        when (version) {
+                            is ProviderVersion.Known -> version.text
+                            // Words, not a colour: there is no way to tell a version this app
+                            // failed to read from one that happens to look odd.
+                            is ProviderVersion.Unknown -> "Version unknown — ${version.why}"
+                        },
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                    // Its own row rather than beside the line above, which is a short string
+                    // when the version is known and a sentence wrapping to four lines when it is
+                    // not — and the second is the state this button matters most in.
+                    Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.End) {
+                        // Disabled rather than absent, so a provider nothing here can update says
+                        // so instead of leaving a reader to wonder where the control went.
+                        TextButton(
+                            onClick = { confirmingUpdate = true },
+                            enabled = view.updatable && busy == null,
+                        ) {
+                            Text("Update")
+                        }
+                    }
+                }
                 Spacer(Modifier.height(12.dp))
                 actionError?.let {
                     Text(it, color = MaterialTheme.colorScheme.error)
@@ -183,6 +216,19 @@ fun ProviderScreen(
                             Spacer(Modifier.height(8.dp))
                         }
                     }
+                    // Where the models would be, because that is what is missing. It is not the
+                    // whole screen's failure: the version above it was read, and the control that
+                    // might fix this is up there too.
+                    view.modelsError?.let { failure ->
+                        item("models-failed") {
+                            Text(
+                                "Models unavailable: $failure",
+                                style = MaterialTheme.typography.bodySmall,
+                                color = MaterialTheme.colorScheme.error,
+                            )
+                            Spacer(Modifier.height(8.dp))
+                        }
+                    }
                     machineModels.actionError?.let { failure ->
                         item("models-error") {
                             Text(failure, color = MaterialTheme.colorScheme.error)
@@ -278,6 +324,56 @@ fun ProviderScreen(
         )
     }
 
+    if (confirmingUpdate) {
+        AlertDialog(
+            onDismissRequest = { confirmingUpdate = false },
+            title = {
+                Text("Update ${(state as? LoadState.Loaded)?.value?.name ?: "this provider"}?")
+            },
+            text = {
+                Text(
+                    "The program is updated on ${(state as? LoadState.Loaded)?.value?.machine ?: "its machine"}, " +
+                        "which every session there uses. Sessions already running keep the version they " +
+                        "started with; the next one to start gets the new one. Nothing here can answer a " +
+                        "password prompt, so an update needing one stops rather than waits."
+                )
+            },
+            confirmButton = {
+                TextButton(
+                    onClick = {
+                        confirmingUpdate = false
+                        act("Updating…") {
+                            updateSaid = updateProvider(settings, machineId, provider).said
+                        }
+                    }
+                ) {
+                    Text("Update")
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { confirmingUpdate = false }) { Text("Cancel") }
+            },
+        )
+    }
+
+    updateSaid?.let { said ->
+        AlertDialog(
+            onDismissRequest = { updateSaid = null },
+            title = { Text("The updater said") },
+            text = {
+                // Its own words, monospace and scrollable: this is a program's output, and the
+                // sentence that matters is as often "use your package manager" as it is a version.
+                Text(
+                    said,
+                    style = MaterialTheme.typography.bodySmall,
+                    fontFamily = FontFamily.Monospace,
+                    modifier = Modifier.verticalScroll(rememberScrollState()),
+                )
+            },
+            confirmButton = { TextButton(onClick = { updateSaid = null }) { Text("Done") } },
+        )
+    }
+
     if (confirmingStop) {
         AlertDialog(
             onDismissRequest = { confirmingStop = false },

server/src/config.rs

@@ -94,8 +94,28 @@ pub struct ProviderConfig {
     /// Override for the executable, for an install that isn't on PATH.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub command: Option<String>,
-    /// Models offered on the spawn screen. Free text is always allowed
-    /// too; this is a shortcut list, not a restriction.
+    /// What updates this provider's program, for an install its own updater
+    /// will not touch. Run by `sh -c` on the provider's machine, with nothing
+    /// on its stdin.
+    ///
+    /// Config-file only, and deliberately not on any route: the phone must
+    /// never be able to say what runs on a machine -- the same property that
+    /// keeps `LLAMA_BUILDS` a directory rather than a path somebody types. So
+    /// putting a package manager here is a decision made by whoever
+    /// administers that machine, which is also the only person who knows
+    /// whether it can run unattended. Unset, the program's own updater is
+    /// asked ([`DriverKind::update_args`]), which for a packaged install says
+    /// so rather than doing anything.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub update_command: Option<String>,
+    /// Models offered on the spawn screen, for a provider with nothing to ask,
+    /// which is only echo: every other kind's catalog is read from the provider
+    /// itself when a picker opens (`machines::provider_models`).
+    ///
+    /// This said "free text is always allowed too" until 2026-09-23 and it was
+    /// never true of the phone, whose pickers offer what this answers and
+    /// nothing else -- so a list written here was the whole restriction, which
+    /// is what kept a newly released model unreachable.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub models: Vec<String>,
     /// MCP servers whose tools this provider's sessions can use, on top of
@@ -380,6 +400,37 @@ impl DriverKind {
         }
     }
 
+    /// How to ask this kind's program which version it is, and `None` where
+    /// there is no program to ask: echo is this backend.
+    ///
+    /// Reported rather than checked against anything. What the latest release
+    /// is cannot be known from here without asking a service this app has no
+    /// business talking to, so the provider view says which version is
+    /// installed and never that one is out of date -- a claim it would have
+    /// to guess at.
+    pub fn version_args(self) -> Option<&'static [&'static str]> {
+        match self {
+            Self::ClaudeCli | Self::CodexCli | Self::LlamaCpp => Some(&["--version"]),
+            Self::Echo => None,
+        }
+    }
+
+    /// How to ask this kind's program to update itself, and `None` for one
+    /// that has no updater of its own.
+    ///
+    /// Both coding CLIs take `update`, and both answer a packaged install by
+    /// saying to use its package manager rather than by doing something to it
+    /// -- which is the answer worth showing somebody, and is why this is
+    /// asked even where it will not succeed. A llama.cpp build came from
+    /// whoever built it, and echo is this backend: neither has one, and the
+    /// phone draws the control disabled rather than leaving it out.
+    pub fn update_args(self) -> Option<&'static [&'static str]> {
+        match self {
+            Self::ClaudeCli | Self::CodexCli => Some(&["update"]),
+            Self::Echo | Self::LlamaCpp => None,
+        }
+    }
+
     /// The mode used when a new-session form first selects this kind.
     pub fn default_permission_mode(self) -> Option<&'static str> {
         match self {
@@ -799,6 +850,7 @@ impl Config {
             name: ECHO_PROVIDER.to_string(),
             kind: DriverKind::Echo,
             command: None,
+            update_command: None,
             models: Vec::new(),
             mcp_servers: Vec::new(),
             model_settings: BTreeMap::new(),
@@ -909,6 +961,7 @@ mod tests {
                         name: "claude-cli".to_string(),
                         kind: DriverKind::ClaudeCli,
                         command: Some("/usr/bin/claude".to_string()),
+                        update_command: None,
                         models: Vec::new(),
                         mcp_servers: Vec::new(),
                         model_settings: BTreeMap::new(),
@@ -930,6 +983,7 @@ mod tests {
                         name: "claude-cli".to_string(),
                         kind: DriverKind::ClaudeCli,
                         command: None,
+                        update_command: None,
                         models: vec!["haiku".to_string()],
                         mcp_servers: Vec::new(),
                         model_settings: BTreeMap::new(),
@@ -1067,6 +1121,7 @@ sessions: [(
                 name: "claude-cli".to_string(),
                 kind: DriverKind::ClaudeCli,
                 command: Some("/usr/bin/claude".to_string()),
+                update_command: None,
                 models: Vec::new(),
                 mcp_servers: Vec::new(),
                 model_settings: BTreeMap::new(),

server/src/machines.rs

@@ -18,7 +18,6 @@
 
 use anyhow::{Context, Result};
 use serde::Serialize;
-use serde_json::{Value, json};
 
 use crate::config::{DriverKind, ProviderConfig};
 use crate::session::transport::{Launch, Transport};
@@ -36,10 +35,6 @@ const PROBES: &[(&str, &str, DriverKind)] = &[
     ("llama-cpp", "llama-server", DriverKind::LlamaCpp),
 ];
 
-/// Models offered for a discovered Claude CLI. A shortcut list for the spawn
-/// screen, not a restriction -- the field stays free text.
-const CLAUDE_MODELS: &[&str] = &["fable", "opus", "sonnet", "haiku"];
-
 /// Where a machine keeps the llama.cpp builds it has besides the one on its
 /// PATH: one directory per build, holding either `llama-server` itself or the
 /// `bin/llama-server` that `cmake --install` puts there.
@@ -130,10 +125,11 @@ fn probed(found: &str) -> Vec<ProviderConfig> {
             // non-interactive ssh session is not the one a person sees when they
             // log in, so "it is on my PATH" is not enough.
             command: Some(path.to_string()),
-            models: match kind {
-                DriverKind::ClaudeCli => CLAUDE_MODELS.iter().map(|m| (*m).to_string()).collect(),
-                _ => Vec::new(),
-            },
+            // Set by hand if at all, and so kept by `update_machine` across a
+            // re-probe, like the model settings below.
+            update_command: None,
+            // Asked for when a picker opens instead -- see `provider_models`.
+            models: Vec::new(),
             mcp_servers: mcp_defaults(kind),
             // What a probe cannot know: how this machine's models are loaded
             // is configured after the fact, and a re-probe keeps it -- see
@@ -177,7 +173,7 @@ pub struct OfferedModel {
 
 impl OfferedModel {
     /// A model whose id is its own name, which is every provider but llama.
-    fn plain(id: impl Into<String>) -> Self {
+    pub fn plain(id: impl Into<String>) -> Self {
         let id = id.into();
         Self {
             label: id.clone(),
@@ -208,85 +204,161 @@ pub fn mcp_defaults(kind: DriverKind) -> Vec<crate::config::McpServerConfig> {
 
 /// Models the selected provider currently offers on this machine.
 ///
-/// Codex's catalog is account- and CLI-version-specific, so it is asked at the
-/// moment the picker opens rather than copied into `config.ron`. A llama.cpp
-/// provider offers the GGUFs on the machine it runs on, through this same call
-/// -- there was a second route answering that alone, and it went when this one
-/// learned to, because a picker offering a model the spawn screen does not, or
-/// naming it differently, is two answers to one question. Other providers
-/// retain the shortcut list discovery stored for them.
+/// One question with one answer, asked at the moment a picker opens: every
+/// catalog here is a property of the machine, the account or the installed
+/// version rather than of this app, so a list copied into `config.ron` is one
+/// that goes quietly stale. There was a second route answering llama.cpp's
+/// alone, and it went when this one learned to -- a picker offering a model
+/// the spawn screen does not, or naming it differently, is two answers to one
+/// question.
+///
+/// A line per driver and nothing else: what a catalog *is* belongs to the
+/// driver that reads it, and this module knows only which one to ask. A
+/// provider with nothing to ask -- echo -- offers the shortcut list its config
+/// entry carries, which is the one case the config file is the answer.
 pub async fn provider_models(
     transport: &Transport,
     provider: &ProviderConfig,
     models_dir: &std::path::Path,
 ) -> Result<Vec<OfferedModel>> {
-    if provider.kind == DriverKind::LlamaCpp {
-        let dir = crate::models::dir_on(transport, models_dir);
-        let mut found = crate::models::on_machine(transport, &dir).await?;
-        // A vision model's projector is a file beside it rather than a model,
-        // and the session that reads pictures is the one on the model: offered
-        // here it is a chip that starts a server which cannot load it. It is
-        // still in the machine's own model list, which is where a file on a
-        // disk is managed and deleted.
-        found.retain(|model| {
-            !crate::session::llama::is_projector(model.key.rsplit('/').next().unwrap_or_default())
-        });
-        let labels = crate::models::labels(&found);
-        return Ok(found
-            .into_iter()
-            .zip(labels)
-            .map(|(model, label)| OfferedModel {
-                id: model.key,
-                label,
-            })
-            .collect());
+    match provider.kind {
+        DriverKind::ClaudeCli => crate::session::claude::list_models(transport, provider).await,
+        DriverKind::CodexCli => crate::session::codex::list_models(transport, provider).await,
+        DriverKind::LlamaCpp => crate::session::llama::list_models(transport, models_dir).await,
+        DriverKind::Echo => Ok(provider.models.iter().map(OfferedModel::plain).collect()),
     }
-    if provider.kind != DriverKind::CodexCli {
-        return Ok(provider.models.iter().map(OfferedModel::plain).collect());
-    }
-    let transport = transport.clone();
-    let program = provider.program().to_string();
-    tokio::task::spawn_blocking(move || {
-        let launch = Launch::new(program, vec!["app-server".into(), "--stdio".into()], None);
-        let initial = json!({
-            "id": 1,
-            "method": "initialize",
-            "params": {"clientInfo": {"name": "ai-app", "title": "AI Sessions", "version": env!("CARGO_PKG_VERSION")}}
-        });
-        let requests = [
-            json!({"method": "initialized"}),
-            json!({"id": 2, "method": "model/list", "params": {"includeHidden": false, "limit": 100}}),
-        ];
-        let answer = transport.request_json_blocking(&launch, &initial, &requests, 2)?;
-        Ok(parse_codex_models(&answer)?
-            .into_iter()
-            .map(OfferedModel::plain)
-            .collect())
-    })
-    .await?
 }
 
-fn parse_codex_models(answer: &Value) -> Result<Vec<String>> {
-    if let Some(message) = answer.pointer("/error/message").and_then(Value::as_str) {
-        anyhow::bail!("Codex could not list models: {message}");
-    }
-    let entries = answer
-        .pointer("/result/data")
-        .and_then(Value::as_array)
-        .context("Codex returned no model catalog")?;
-    let mut models = entries
-        .iter()
-        .filter(|entry| {
-            !entry
-                .get("hidden")
-                .and_then(Value::as_bool)
-                .unwrap_or(false)
-        })
-        .filter_map(|entry| entry.get("model").and_then(Value::as_str))
+/// How long an update is given before it is killed.
+///
+/// Generous because the work is a download -- the Claude CLI is a couple of
+/// hundred megabytes -- and because the machine may be on the far end of a
+/// tunnel. It is a backstop rather than a budget: what it is really there for
+/// is a command that stopped to ask something, which with no stdin to read is
+/// a wait nothing ends.
+const UPDATE_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(600);
+
+/// Which version of its program a provider has, or why that could not be
+/// asked.
+///
+/// Two states rather than an `Option<String>`, because "this machine could not
+/// be reached" and "this provider has no version" are different things to draw
+/// and an absent string is both. A kind with no program to ask -- echo -- has
+/// neither, and reports `None`.
+#[derive(Debug, Clone, Serialize)]
+#[serde(rename_all = "camelCase", tag = "state", content = "text")]
+pub enum Version {
+    Known(String),
+    Unknown(String),
+}
+
+/// Asks a provider's program which version it is.
+///
+/// Trimmed to its first line: the programs here answer with one, and a program
+/// that decides to print its licence after it is not going to be drawn in a
+/// row beside a button.
+///
+/// **Either stream, and only from a run that succeeded.** `llama-server`
+/// prints its version to stderr and both CLIs print theirs to stdout, so
+/// reading one of them is right for some of the programs this asks -- it drew
+/// "Version unknown" over a version that was sitting on the other pipe. What
+/// the exit status is for is the case that makes taking stderr dangerous: a
+/// program that is not installed also writes to stderr, and "command not
+/// found" must not be shown where a version goes.
+pub async fn provider_version(transport: &Transport, provider: &ProviderConfig) -> Option<Version> {
+    let args = provider.kind.version_args()?;
+    let launch = Launch::new(
+        provider.program(),
+        args.iter().map(|a| (*a).to_string()).collect(),
+        None,
+    );
+    Some(
+        match transport
+            .capture_with_input(&launch, crate::session::transport::Input::None)
+            .await
+        {
+            Ok(captured) if captured.status.success() => {
+                let stdout = String::from_utf8_lossy(&captured.stdout);
+                match first_line(&stdout).or_else(|| first_line(&captured.stderr)) {
+                    Some(line) => Version::Known(line),
+                    // It ran and said nothing, which is not a version and must
+                    // not be drawn as one.
+                    None => Version::Unknown("it printed no version".to_string()),
+                }
+            }
+            Ok(captured) => Version::Unknown(if captured.stderr.is_empty() {
+                format!("it exited {}", captured.status)
+            } else {
+                captured.stderr
+            }),
+            Err(err) => Version::Unknown(explain(err).to_string()),
+        },
+    )
+}
+
+fn first_line(text: &str) -> Option<String> {
+    text.lines()
+        .map(str::trim)
+        .find(|line| !line.is_empty())
         .map(str::to_string)
-        .collect::<Vec<_>>();
-    models.dedup();
-    Ok(models)
+}
+
+/// Updates a provider's program on its own machine, and reports what that
+/// said.
+///
+/// The output whole rather than a verdict read out of it: an updater that
+/// declines -- "Claude is managed by a package manager" is the answer on every
+/// install here -- is saying the one thing somebody needs, and a boolean
+/// success would throw it away. So this fails only where the command could not
+/// be run at all, and a command that ran and refused is an answer.
+///
+/// Nothing on its stdin, which is what keeps a command that stops to ask
+/// something from waiting for ever; [`UPDATE_TIMEOUT`] is the backstop for one
+/// that waits on something else.
+pub async fn update_provider(transport: &Transport, provider: &ProviderConfig) -> Result<String> {
+    let launch = match &provider.update_command {
+        Some(command) => Launch::new("sh", vec!["-c".to_string(), command.clone()], None),
+        None => {
+            let args = provider.kind.update_args().with_context(|| {
+                format!(
+                    "\"{}\" has no updater of its own -- an `updateCommand` on it in this backend's config file is what updates it",
+                    provider.name,
+                )
+            })?;
+            Launch::new(
+                provider.program(),
+                args.iter().map(|a| (*a).to_string()).collect(),
+                None,
+            )
+        }
+    };
+    let captured = tokio::time::timeout(
+        UPDATE_TIMEOUT,
+        transport.capture_with_input(&launch, crate::session::transport::Input::None),
+    )
+    .await
+    .map_err(|_| {
+        anyhow::anyhow!(
+            "it was still going after {} minutes and was stopped. A command that needs a \
+             password cannot be answered from here.",
+            UPDATE_TIMEOUT.as_secs() / 60,
+        )
+    })?
+    .map_err(explain)?;
+    // stderr as well, and after: the CLIs write their progress to one and their
+    // refusals to the other, and which of them carried the sentence that
+    // matters is not a thing to guess at.
+    let mut said = String::from_utf8_lossy(&captured.stdout).trim().to_string();
+    if !captured.stderr.is_empty() {
+        if !said.is_empty() {
+            said.push('\n');
+        }
+        said.push_str(&captured.stderr);
+    }
+    if said.is_empty() {
+        said = format!("it said nothing ({})", captured.status);
+    }
+    Ok(said)
 }
 
 /// Adds what to do to failures whose own wording does not say.
@@ -434,26 +506,4 @@ mod tests {
         assert_eq!(providers.len(), 1);
         assert_eq!(providers[0].name, "codex-cli");
     }
-
-    #[test]
-    fn codex_models_are_the_selectable_non_hidden_catalog_entries() {
-        let answer = json!({"result": {"data": [
-            {"model": "gpt-small", "hidden": false},
-            {"model": "gpt-hidden", "hidden": true},
-            {"model": "gpt-large", "hidden": false}
-        ]}});
-        assert_eq!(
-            parse_codex_models(&answer).unwrap(),
-            vec!["gpt-small".to_string(), "gpt-large".to_string()]
-        );
-    }
-
-    #[test]
-    fn a_failed_codex_catalog_is_not_reported_as_an_empty_one() {
-        let answer = json!({"error": {"message": "login required"}});
-        assert_eq!(
-            parse_codex_models(&answer).unwrap_err().to_string(),
-            "Codex could not list models: login required"
-        );
-    }
 }

server/src/provider_auth.rs

@@ -433,6 +433,7 @@ mod tests {
         };
         let provider = ProviderConfig {
             name: "claude-cli".to_string(),
+            update_command: None,
             kind: DriverKind::ClaudeCli,
             command: Some(cli.display().to_string()),
             models: Vec::new(),

server/src/routes.rs

@@ -12,6 +12,7 @@
 //! POST   /machines/{id}/providers/{provider}/settings  {maxLoaded} -- null for the default
 //! POST   /machines/{id}/providers/{provider}/model-settings  {model, params} -- how it loads
 //! POST   /machines/{id}/providers/{provider}/stop   end the machine's shared server
+//! POST   /machines/{id}/providers/{provider}/update update its program on its machine
 //! POST   /machines/{id}/providers/{provider}/unload {model} -- out of memory, server stays
 //! GET    /machines/{id}/providers/{provider}/models  models that provider offers
 //! POST   /machines/{id}/providers/{provider}/auth    begin provider sign-in
@@ -180,6 +181,13 @@ pub fn router(manager: Arc<SessionManager>) -> Router {
             "/machines/{id}/providers/{provider}/settings",
             post(set_provider_settings),
         )
+        // Updating the program a provider runs, on its own machine. A POST
+        // with no body: what runs is the driver's own updater or what the
+        // config file names, never anything the phone sends.
+        .route(
+            "/machines/{id}/providers/{provider}/update",
+            post(update_provider),
+        )
         .route(
             "/machines/{id}/providers/{provider}/model-settings",
             post(set_model_settings),
@@ -682,9 +690,27 @@ struct ProviderView {
     #[serde(skip_serializing_if = "Option::is_none")]
     max_loaded: Option<u32>,
     models: Vec<ProviderModel>,
+    /// Why the catalog could not be read, where it could not be.
+    ///
+    /// Carried rather than failing the whole answer, because a provider whose
+    /// program cannot be asked is exactly the one somebody came here to
+    /// update: refusing the screen took the version and the Update button
+    /// away at the only moment they were the point.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    models_error: Option<String>,
     /// The tools this provider's sessions have over and above its own.
     #[serde(skip_serializing_if = "Vec::is_empty")]
     mcp_servers: Vec<String>,
+    /// Which version of its program is installed, and `None` for a kind with
+    /// no program to ask. Never compared against a latest release: what that
+    /// is cannot be known from here, and "up to date" is not a thing to guess.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    version: Option<crate::machines::Version>,
+    /// Whether anything here can update it -- its own updater, or a command
+    /// the config file names. The control is drawn either way and disabled
+    /// when this is false, so that a provider nothing updates says so rather
+    /// than leaving a reader wondering where the button went.
+    updatable: bool,
     /// Its shared server, or `None` for a provider that has none. The
     /// difference matters on screen: "nothing is loaded" and "there is nothing
     /// here to load" are not the same sentence.
@@ -725,9 +751,16 @@ async fn provider_view(
     let machine = machine_by_id(&manager, &id)?;
     let provider = provider_on(&machine, &provider_name)?.clone();
     let transport = crate::session::transport::Transport::for_machine(&machine);
-    let offered = crate::machines::provider_models(&transport, &provider, manager.models_dir())
-        .await
-        .map_err(from_machine)?;
+    // Together rather than one after the other: both are a process started on
+    // that machine, and on a remote one each is a round trip down the tunnel.
+    let (offered, version) = tokio::join!(
+        crate::machines::provider_models(&transport, &provider, manager.models_dir()),
+        crate::machines::provider_version(&transport, &provider),
+    );
+    let (offered, models_error) = match offered {
+        Ok(offered) => (offered, None),
+        Err(err) => (Vec::new(), Some(format!("{err:#}"))),
+    };
     let router = manager.router_for(&machine, &provider);
     // Asked of the server only when there is one running: a router that is
     // down has no opinion about which models are loaded, and inventing
@@ -765,8 +798,11 @@ async fn provider_view(
         kind: provider.kind,
         command: provider.command,
         model_params: provider.kind.model_params(),
+        version,
+        updatable: provider.update_command.is_some() || provider.kind.update_args().is_some(),
         max_loaded: provider.max_loaded,
         models,
+        models_error,
         mcp_servers: provider
             .mcp_servers
             .iter()
@@ -783,6 +819,36 @@ async fn provider_view(
     }))
 }
 
+/// What an update said, whether or not it did anything.
+///
+/// Its output and nothing else. The version it left behind is deliberately not
+/// here: the screen refetches the provider once the action finishes, which
+/// reads the version anyway, and answering with one as well would be the same
+/// fact arriving twice -- two processes started on that machine to ask one
+/// question, and two places for it to disagree.
+#[derive(serde::Serialize)]
+#[serde(rename_all = "camelCase")]
+struct UpdateResult {
+    /// The updater's own output. Shown as it came: an updater declining to
+    /// touch a packaged install is saying what to do instead, and a verdict
+    /// read out of this would drop that sentence.
+    said: String,
+}
+
+/// Updates the program one provider runs, on the machine it runs on.
+async fn update_provider(
+    State(manager): State<Arc<SessionManager>>,
+    UrlPath((id, provider_name)): UrlPath<(String, String)>,
+) -> Result<axum::Json<UpdateResult>, ApiError> {
+    let machine = machine_by_id(&manager, &id)?;
+    let provider = provider_on(&machine, &provider_name)?.clone();
+    let transport = crate::session::transport::Transport::for_machine(&machine);
+    let said = crate::machines::update_provider(&transport, &provider)
+        .await
+        .map_err(from_machine)?;
+    Ok(axum::Json(UpdateResult { said }))
+}
+
 /// What the provider itself takes, as opposed to what one of its models does.
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]

server/src/session/claude.rs

@@ -63,6 +63,7 @@ use super::process;
 use super::subagent::Subagents;
 use super::transport::{Launch, Streams, Transport};
 use crate::config::{ProviderConfig, SessionConfig};
+use crate::machines::OfferedModel;
 use translate::{AnswerOutcome, Setting, Translator, starts_a_model_call};
 
 /// How much of a failing process's stderr the exit report carries. Enough
@@ -1178,6 +1179,87 @@ fn attachment_block(session_dir: &Path, id: &str) -> Result<Value> {
     }))
 }
 
+/// What the Claude CLI on this machine says it can run.
+///
+/// Its `/model` picker is built from a catalog inside the binary, so which
+/// models exist is a property of the installed version and of the account --
+/// `opus` resolved to Opus 5 before 2.1.280 and to Opus 5.5 after it, with no
+/// change here. Asking is the only way to be right about that, and a list
+/// written in this file is wrong from the next release onwards.
+///
+/// The control channel rather than a flag, because the CLI has no listing
+/// command: `list_models` is the same channel the driver already sends
+/// `set_model` down, and it answers a process started with nothing to say.
+pub async fn list_models(
+    transport: &Transport,
+    provider: &ProviderConfig,
+) -> Result<Vec<OfferedModel>> {
+    let transport = transport.clone();
+    let program = provider.program().to_string();
+    tokio::task::spawn_blocking(move || {
+        let args = [
+            "-p",
+            "--verbose",
+            "--input-format",
+            "stream-json",
+            "--output-format",
+            "stream-json",
+        ];
+        let launch = Launch::new(
+            program,
+            args.iter().map(|a| (*a).to_string()).collect(),
+            None,
+        );
+        let request = json!({
+            "type": "control_request",
+            "request_id": "models",
+            "request": {"subtype": "list_models"},
+        });
+        let answer = transport.request_json_blocking(&launch, None, &[request], |value| {
+            value.get("type").and_then(Value::as_str) == Some("control_response")
+        })?;
+        parse_models(&answer)
+    })
+    .await?
+}
+
+fn parse_models(answer: &Value) -> Result<Vec<OfferedModel>> {
+    if let Some(message) = answer.pointer("/response/error").and_then(Value::as_str) {
+        anyhow::bail!("the Claude CLI could not list models: {message}");
+    }
+    let entries = answer
+        .pointer("/response/response/models")
+        .and_then(Value::as_array)
+        .context("the Claude CLI returned no model catalog")?;
+    Ok(entries
+        .iter()
+        // A row the installed version cannot actually run -- it names the
+        // version that could. Offered, it is a chip that starts a session and
+        // fails; the honest place to say a CLI is out of date is the provider
+        // view, which reports the version and can update it.
+        .filter(|entry| {
+            !entry
+                .get("disabled")
+                .and_then(Value::as_bool)
+                .unwrap_or(false)
+        })
+        .filter_map(|entry| {
+            let id = entry.get("value").and_then(Value::as_str)?;
+            Some(OfferedModel {
+                id: id.to_string(),
+                // The CLI's own words for it, which is what its `/model` picker
+                // shows: two rows can resolve to one model and differ only in
+                // the window they ask for, and the id is where that is written.
+                label: entry
+                    .get("displayName")
+                    .and_then(Value::as_str)
+                    .unwrap_or(id)
+                    .to_string(),
+            })
+        })
+        .collect())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -1752,4 +1834,35 @@ mod tests {
         assert!(forget_resume_token(dir.path()));
         assert_eq!(read_resume_token(dir.path()), None);
     }
+
+    /// The real shape, from 2.1.281 on this machine. The disabled row is what
+    /// the CLI reports for a model the installed version cannot run yet, and
+    /// offering it is a chip that fails at the spawn.
+    #[test]
+    fn a_claude_model_the_installed_cli_cannot_run_is_not_offered() {
+        let answer = json!({"type": "control_response", "response": {"subtype": "success", "response": {"models": [
+            {"value": "default", "resolvedModel": "claude-opus-5-5[1m]", "displayName": "Default (recommended)"},
+            {"value": "haiku", "resolvedModel": "claude-haiku-4-5-20251001", "displayName": "Haiku"},
+            {"value": "cc-update-required-1", "displayName": "Opus 5.5 (disabled)", "disabled": true}
+        ]}}});
+        let offered = parse_models(&answer).unwrap();
+        assert_eq!(
+            offered.iter().map(|m| m.id.as_str()).collect::<Vec<_>>(),
+            vec!["default", "haiku"]
+        );
+        // The CLI's own words, since two rows can name one model and differ
+        // only in the context window they ask for.
+        assert_eq!(offered[0].label, "Default (recommended)");
+    }
+
+    #[test]
+    fn a_failed_claude_catalog_is_not_reported_as_an_empty_one() {
+        let answer = json!({"type": "control_response", "response": {"error": "not logged in"}});
+        assert_eq!(
+            parse_models(&answer).unwrap_err().to_string(),
+            "the Claude CLI could not list models: not logged in"
+        );
+        // A response of a shape nobody here has seen is also not "no models".
+        assert!(parse_models(&json!({"type": "control_response"})).is_err());
+    }
 }

server/src/session/codex.rs

@@ -28,6 +28,7 @@ use super::process;
 use super::subagent::Subagents;
 use super::transport::{Launch, Streams, Transport};
 use crate::config::{ProviderConfig, SessionConfig};
+use crate::machines::OfferedModel;
 use translate::Translator;
 
 const STDIN_FIFO: &str = "codex-stdin.fifo";
@@ -1483,6 +1484,65 @@ fn valid_thread_id(id: &str) -> bool {
             .all(|character| character.is_ascii_hexdigit() || character == '-')
 }
 
+/// What the Codex CLI on this machine says the account can run.
+///
+/// Asked at the moment the picker opens rather than copied into `config.ron`:
+/// the catalog is account- and CLI-version-specific, so a list written down
+/// here is a claim about somebody else's subscription.
+pub async fn list_models(
+    transport: &Transport,
+    provider: &ProviderConfig,
+) -> Result<Vec<OfferedModel>> {
+    let transport = transport.clone();
+    let program = provider.program().to_string();
+    tokio::task::spawn_blocking(move || {
+        let launch = Launch::new(program, vec!["app-server".into(), "--stdio".into()], None);
+        let initial = json!({
+            "id": 1,
+            "method": "initialize",
+            "params": {"clientInfo": {"name": "ai-app", "title": "AI Sessions", "version": env!("CARGO_PKG_VERSION")}}
+        });
+        let requests = [
+            json!({"method": "initialized"}),
+            json!({"id": 2, "method": "model/list", "params": {"includeHidden": false, "limit": 100}}),
+        ];
+        let answer = transport.request_json_blocking(
+            &launch,
+            Some(&initial),
+            &requests,
+            Transport::answer_to(2),
+        )?;
+        Ok(parse_models(&answer)?
+            .into_iter()
+            .map(OfferedModel::plain)
+            .collect())
+    })
+    .await?
+}
+
+fn parse_models(answer: &Value) -> Result<Vec<String>> {
+    if let Some(message) = answer.pointer("/error/message").and_then(Value::as_str) {
+        anyhow::bail!("Codex could not list models: {message}");
+    }
+    let entries = answer
+        .pointer("/result/data")
+        .and_then(Value::as_array)
+        .context("Codex returned no model catalog")?;
+    let mut models = entries
+        .iter()
+        .filter(|entry| {
+            !entry
+                .get("hidden")
+                .and_then(Value::as_bool)
+                .unwrap_or(false)
+        })
+        .filter_map(|entry| entry.get("model").and_then(Value::as_str))
+        .map(str::to_string)
+        .collect::<Vec<_>>();
+    models.dedup();
+    Ok(models)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -2033,4 +2093,26 @@ mod tests {
         assert_eq!(retried["params"]["clientUserMessageId"], "client-message");
         assert_eq!(retried["params"]["input"][0]["text"], "do not lose me");
     }
+
+    #[test]
+    fn codex_models_are_the_selectable_non_hidden_catalog_entries() {
+        let answer = json!({"result": {"data": [
+            {"model": "gpt-small", "hidden": false},
+            {"model": "gpt-hidden", "hidden": true},
+            {"model": "gpt-large", "hidden": false}
+        ]}});
+        assert_eq!(
+            parse_models(&answer).unwrap(),
+            vec!["gpt-small".to_string(), "gpt-large".to_string()]
+        );
+    }
+
+    #[test]
+    fn a_failed_codex_catalog_is_not_reported_as_an_empty_one() {
+        let answer = json!({"error": {"message": "login required"}});
+        assert_eq!(
+            parse_models(&answer).unwrap_err().to_string(),
+            "Codex could not list models: login required"
+        );
+    }
 }

server/src/session/llama/mod.rs

@@ -2124,6 +2124,35 @@ pub struct Model {
     mmproj: Option<String>,
 }
 
+/// The GGUFs the machine serving this provider has, as models to pick from.
+///
+/// A file on a disk rather than a catalog somebody publishes, which is why the
+/// id and the label differ here and nowhere else: the id is the path the
+/// server is pointed at, and the label is the name the file's own metadata
+/// gives it.
+pub async fn list_models(
+    transport: &Transport,
+    models_dir: &Path,
+) -> Result<Vec<crate::machines::OfferedModel>> {
+    let dir = crate::models::dir_on(transport, models_dir);
+    let mut found = crate::models::on_machine(transport, &dir).await?;
+    // A vision model's projector is a file beside it rather than a model, and
+    // the session that reads pictures is the one on the model: offered here it
+    // is a chip that starts a server which cannot load it. It is still in the
+    // machine's own model list, which is where a file on a disk is managed and
+    // deleted.
+    found.retain(|model| !is_projector(model.key.rsplit('/').next().unwrap_or_default()));
+    let labels = crate::models::labels(&found);
+    Ok(found
+        .into_iter()
+        .zip(labels)
+        .map(|(model, label)| crate::machines::OfferedModel {
+            id: model.key,
+            label,
+        })
+        .collect())
+}
+
 /// Whether a file lying beside a model is a multimodal projector for it.
 ///
 /// By name, which is the only thing both sides of this can see cheaply: the

server/src/session/mod.rs

@@ -1068,6 +1068,9 @@ impl SessionManager {
                     if let Some(old) = machine.provider(&provider.name) {
                         provider.model_settings = old.model_settings.clone();
                         provider.max_loaded = old.max_loaded;
+                        // Same reason: a probe finds programs, and this was set
+                        // by hand in the config file.
+                        provider.update_command = old.update_command.clone();
                     }
                 }
                 machine.providers = providers;
@@ -4326,6 +4329,7 @@ mod tests {
                 Config::echo_provider(),
                 ProviderConfig {
                     name: "stand-in".to_string(),
+                    update_command: None,
                     kind: DriverKind::ClaudeCli,
                     command: Some(command.to_string_lossy().into_owned()),
                     models: Vec::new(),

server/src/session/transport.rs

@@ -102,19 +102,35 @@ pub enum Transport {
 }
 
 impl Transport {
-    /// Exchanges newline-delimited JSON requests with a short-lived stdio
-    /// server. `initial` is written first; after its response arrives,
-    /// `requests` is written and the response bearing `wanted_id` is returned.
+    /// Accepts the JSON-RPC answer carrying `id`, for
+    /// [`Transport::request_json_blocking`]'s `wanted`.
     ///
-    /// This is the shape Codex's app-server requires for a usage read: an
-    /// initialize round trip must finish before the initialized notification
-    /// and account request are accepted.
+    /// Named rather than written at each call because both of Codex's stdio
+    /// reads want it and neither of them is where somebody would look for the
+    /// other.
+    pub fn answer_to(id: u64) -> impl Fn(&serde_json::Value) -> bool {
+        move |value| value.get("id").and_then(serde_json::Value::as_u64) == Some(id)
+    }
+
+    /// Exchanges newline-delimited JSON requests with a short-lived stdio
+    /// server. `handshake` is written first and its response waited for;
+    /// `requests` is written after that, and the first response `wanted`
+    /// accepts is returned.
+    ///
+    /// The handshake is optional because the two protocols spoken here differ
+    /// on it rather than in kind: Codex's app-server refuses the initialized
+    /// notification and everything after it until an initialize round trip has
+    /// finished, while Claude Code's control channel answers a request written
+    /// the moment the process starts. `wanted` is a predicate for the same
+    /// reason -- one addresses its answers by a numeric `id` and the other by
+    /// a string `request_id`, which is a difference in where the answer's name
+    /// is written and not in what this does.
     pub fn request_json_blocking(
         &self,
         launch: &Launch,
-        initial: &serde_json::Value,
+        handshake: Option<&serde_json::Value>,
         requests: &[serde_json::Value],
-        wanted_id: u64,
+        wanted: impl Fn(&serde_json::Value) -> bool,
     ) -> Result<serde_json::Value> {
         use std::io::{BufRead, BufReader, Write};
 
@@ -141,22 +157,24 @@ impl Transport {
             .stdout
             .take()
             .context("the JSON server has no stdout")?;
-        writeln!(stdin, "{initial}")?;
-        stdin.flush()?;
         let mut reader = BufReader::new(stdout);
         let mut line = String::new();
-        loop {
-            line.clear();
-            if reader.read_line(&mut line)? == 0 {
-                anyhow::bail!("the JSON server exited before initialization completed");
-            }
-            let Ok(value) = serde_json::from_str::<serde_json::Value>(&line) else {
-                continue;
-            };
-            if value.get("id").and_then(serde_json::Value::as_u64)
-                == initial.get("id").and_then(serde_json::Value::as_u64)
-            {
-                break;
+        if let Some(handshake) = handshake {
+            writeln!(stdin, "{handshake}")?;
+            stdin.flush()?;
+            loop {
+                line.clear();
+                if reader.read_line(&mut line)? == 0 {
+                    anyhow::bail!("the JSON server exited before initialization completed");
+                }
+                let Ok(value) = serde_json::from_str::<serde_json::Value>(&line) else {
+                    continue;
+                };
+                if value.get("id").and_then(serde_json::Value::as_u64)
+                    == handshake.get("id").and_then(serde_json::Value::as_u64)
+                {
+                    break;
+                }
             }
         }
         for request in requests {
@@ -166,12 +184,12 @@ impl Transport {
         loop {
             line.clear();
             if reader.read_line(&mut line)? == 0 {
-                anyhow::bail!("the JSON server exited before answering request {wanted_id}");
+                anyhow::bail!("the JSON server exited before answering");
             }
             let Ok(value) = serde_json::from_str::<serde_json::Value>(&line) else {
                 continue;
             };
-            if value.get("id").and_then(serde_json::Value::as_u64) == Some(wanted_id) {
+            if wanted(&value) {
                 let _ = child.kill();
                 let _ = child.wait();
                 return Ok(value);

server/src/usage.rs

@@ -282,10 +282,12 @@ impl UsageProvider for CodexUsage {
             serde_json::json!({"method": "initialized"}),
             serde_json::json!({"id": 2, "method": "account/rateLimits/read"}),
         ];
-        let answer = match self
-            .transport
-            .request_json_blocking(&launch, &initialized, &requests, 2)
-        {
+        let answer = match self.transport.request_json_blocking(
+            &launch,
+            Some(&initialized),
+            &requests,
+            Transport::answer_to(2),
+        ) {
             Ok(answer) => answer,
             Err(err) => {
                 return vec![self.snapshot(
@@ -1105,6 +1107,7 @@ mod tests {
             }),
             providers: vec![crate::config::ProviderConfig {
                 name: "claude-cli".to_string(),
+                update_command: None,
                 kind: DriverKind::ClaudeCli,
                 command: None,
                 models: vec![],
@@ -1171,6 +1174,7 @@ mod tests {
         let mut echo_only = unreachable_machine();
         echo_only.providers = vec![crate::config::ProviderConfig {
             name: "echo".to_string(),
+            update_command: None,
             kind: DriverKind::Echo,
             command: None,
             models: vec![],