fix(mobile): phone Claude Code follows Claude's update channel, latest by default

apps/mobile/modules/t3-device-runtime/android/src/main/assets/device-runtime-setup.sh

@@ -4,7 +4,8 @@ set -euo pipefail
 export DEBIAN_FRONTEND=noninteractive
 export PATH="$HOME/.local/bin:$PATH"
 NODE_CHANNEL=https://nodejs.org/dist/latest-v24.x
-CLAUDE_LIST=/etc/apt/sources.list.d/claude-code.list
+CLAUDE_LIST=${CLAUDE_LIST:-/etc/apt/sources.list.d/claude-code.list}
+CLAUDE_MANAGED=${CLAUDE_MANAGED:-/etc/claude-code}
 # The fork whose releases carry a Linux arm64 server (FORK.md).
 RELEASE_REPO=tebiggs/t3code
 T3_LINK="$HOME/.local/bin/t3"
@@ -55,20 +56,41 @@ step_node() {
   done
 }
 
-# Anthropic's stable channel. The app checks the signing key's fingerprint and writes it
-# first. One copy of the binary, updated only through apt.
+# Anthropic's apt repository for the channel Claude Code's settings pick. The app checks the
+# signing key's fingerprint and writes it first. One copy of the binary, updated only through apt.
 step_claude_code() {
   [ -s /etc/apt/keyrings/claude-code.asc ] || { echo "Claude Code's signing key is missing." >&2; exit 1; }
-  echo "deb [signed-by=/etc/apt/keyrings/claude-code.asc] https://downloads.claude.ai/claude-code/apt/stable stable main" > "$CLAUDE_LIST"
+  write_claude_list
   update_claude_repo
   apt_install claude-code
 }
 
+# Moving to stable keeps a newer build until stable passes it.
 step_upgrade_claude_code() {
+  write_claude_list
   update_claude_repo
   apt-get install -y --only-upgrade claude-code
 }
 
+write_claude_list() {
+  channel=$(claude_channel)
+  echo "deb [signed-by=/etc/apt/keyrings/claude-code.asc] https://downloads.claude.ai/claude-code/apt/$channel $channel main" > "$CLAUDE_LIST"
+  echo "Claude Code channel: $channel"
+}
+
+# autoUpdatesChannel, latest by default as in Claude Code. Later files win, as in the server's
+# ClaudeMaintenance.readUpdateChannel.
+claude_channel() {
+  channel=latest
+  for file in "${CLAUDE_CONFIG_DIR:-$HOME/.claude}/settings.json" "$CLAUDE_MANAGED/managed-settings.json" \
+    "$CLAUDE_MANAGED"/managed-settings.d/*.json; do
+    [ -f "$file" ] || continue
+    value=$(sed -n 's/.*"autoUpdatesChannel"[[:space:]]*:[[:space:]]*"\(latest\|stable\)".*/\1/p' "$file" | tail -n 1)
+    if [ -n "$value" ]; then channel=$value; fi
+  done
+  echo "$channel"
+}
+
 update_claude_repo() {
   apt-get update -o Dir::Etc::SourceList="$CLAUDE_LIST" -o Dir::Etc::SourceParts=- -o APT::Get::List-Cleanup=0
 }

apps/mobile/src/features/device-runtime/device-runtime-script.test.ts

@@ -30,6 +30,7 @@ ln -sfn "$HOME/.t3/runtime/versions/$T3CODE_VERSION/t3" "$HOME/.local/bin/t3"
 `;
 
 interface Guest {
+  readonly root: string;
   readonly home: string;
   readonly log: string;
   run(step: string): string;
@@ -64,6 +65,7 @@ esac
 `,
   );
   writeExecutable(NodePath.join(bin, "node"), "#!/bin/sh\necho v24.22.1\n");
+  writeExecutable(NodePath.join(bin, "apt-get"), `#!/bin/sh\necho "apt-get $*" >> "$STUB_LOG"\n`);
   writeExecutable(
     NodePath.join(bin, "claude"),
     `#!/bin/sh
@@ -75,13 +77,21 @@ esac
   );
   const versions = NodePath.join(home, ".t3/runtime/versions");
   return {
+    root,
     home,
     log,
     run(step) {
       return NodeChildProcess.execFileSync("bash", ["-s", "--", step], {
         input: SCRIPT,
         encoding: "utf8",
-        env: { NODE_ENV: "test", HOME: home, PATH: `${bin}:/usr/bin:/bin`, STUB_LOG: log },
+        env: {
+          NODE_ENV: "test",
+          HOME: home,
+          PATH: `${bin}:/usr/bin:/bin`,
+          STUB_LOG: log,
+          CLAUDE_LIST: NodePath.join(root, "claude-code.list"),
+          CLAUDE_MANAGED: NodePath.join(root, "claude-code"),
+        },
       });
     },
     version(name) {
@@ -132,6 +142,36 @@ describe("device-runtime-setup.sh", () => {
     expect(NodeFS.readFileSync(guest.log, "utf8")).toBe("");
   });
 
+  it.each([
+    { settings: {}, channel: "latest" },
+    {
+      settings: { ".claude/settings.json": '{ "autoUpdatesChannel": "stable" }' },
+      channel: "stable",
+    },
+    {
+      settings: {
+        ".claude/settings.json": '{"autoUpdatesChannel":"stable"}',
+        "claude-code/managed-settings.json": "{}",
+        "claude-code/managed-settings.d/10-channel.json": '{\n  "autoUpdatesChannel": "latest"\n}',
+      },
+      channel: "latest",
+    },
+  ])("upgrades Claude Code from the $channel apt repository its settings pick", (row) => {
+    using guest = makeGuest();
+    for (const [file, text] of Object.entries(row.settings)) {
+      const path = NodePath.join(file.startsWith(".claude") ? guest.home : guest.root, file);
+      NodeFS.mkdirSync(NodePath.dirname(path), { recursive: true });
+      NodeFS.writeFileSync(path, text);
+    }
+    guest.run("upgrade-claude-code");
+    expect(NodeFS.readFileSync(NodePath.join(guest.root, "claude-code.list"), "utf8")).toBe(
+      `deb [signed-by=/etc/apt/keyrings/claude-code.asc] https://downloads.claude.ai/claude-code/apt/${row.channel} ${row.channel} main\n`,
+    );
+    expect(NodeFS.readFileSync(guest.log, "utf8")).toContain(
+      "apt-get install -y --only-upgrade claude-code",
+    );
+  });
+
   it("reports versions and the Claude sign-in for the app", () => {
     using guest = makeGuest();
     guest.link("0.1.3");