Agent pane: a subagent's own pane shows it read only, without the chat's composer, queue or PR bars

webviews/src/agent-session/acpmux/Localizable.xcstrings

@@ -120620,6 +120620,138 @@
         }
       }
     },
+    "subagents.paneReadOnly": {
+      "comment": "Agent pane: where a subagent's own pane would show the chat's composer; {name} is the chat that takes messages",
+      "extractionState": "manual",
+      "localizations": {
+        "en": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Read only · messages go to {name}"
+          }
+        },
+        "ar": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "للقراءة فقط · تُرسل الرسائل إلى {name}"
+          }
+        },
+        "bs": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Samo za čitanje · poruke idu u {name}"
+          }
+        },
+        "da": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Skrivebeskyttet · beskeder går til {name}"
+          }
+        },
+        "de": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Nur lesen · Nachrichten gehen an {name}"
+          }
+        },
+        "es": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Solo lectura · los mensajes van a {name}"
+          }
+        },
+        "fr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Lecture seule · les messages vont à {name}"
+          }
+        },
+        "it": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Sola lettura · i messaggi vanno a {name}"
+          }
+        },
+        "ja": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "閲覧のみ · メッセージは {name} へ"
+          }
+        },
+        "km": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "អានតែប៉ុណ្ណោះ · សារទៅកាន់ {name}"
+          }
+        },
+        "ko": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "읽기 전용 · 메시지는 {name}(으)로"
+          }
+        },
+        "nb": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Skrivebeskyttet · meldinger går til {name}"
+          }
+        },
+        "pl": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Tylko do odczytu · wiadomości trafiają do {name}"
+          }
+        },
+        "pt-BR": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Somente leitura · as mensagens vão para {name}"
+          }
+        },
+        "ru": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Только чтение · сообщения уходят в {name}"
+          }
+        },
+        "th": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "อ่านอย่างเดียว · ข้อความไปที่ {name}"
+          }
+        },
+        "tr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Salt okunur · mesajlar {name} sohbetine gider"
+          }
+        },
+        "uk": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Лише читання · повідомлення йдуть у {name}"
+          }
+        },
+        "vi": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Chỉ đọc · tin nhắn gửi tới {name}"
+          }
+        },
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "只读 · 消息发送到 {name}"
+          }
+        },
+        "zh-Hant": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "唯讀 · 訊息傳送到 {name}"
+          }
+        }
+      }
+    },
     "subagents.open": {
       "comment": "Agent pane",
       "extractionState": "manual",

webviews/src/agent-session/acpmux/header/ChatHeaderTools.tsx

@@ -99,6 +99,7 @@ export function ChatHeaderTools({
   onMenuOpen,
   expand,
   onExpanded,
+  pullRequestChip,
   onMergePullRequest,
   folder,
   readStatus,
@@ -140,6 +141,8 @@ export function ChatHeaderTools({
   /// A row with children to show open (the palette's Continue in…); `onExpanded` clears it.
   expand?: string;
   onExpanded?: () => void;
+  /// The pull request chip (default on); a subagent's own pane draws none: the pull request is the chat's.
+  pullRequestChip?: boolean;
   /// Merge on the PR chip (cx-ncc.77.4): merges that pull request; rejects with why not.
   onMergePullRequest?: (pullRequest: { number: number; url: string }) => Promise<MergeResult>;
   /// The chat's folder on this Mac and its `git.status`: a worktree chat's branch shows (cx-lyqio.3b),
@@ -395,7 +398,9 @@ export function ChatHeaderTools({
   return (
     <div className="acpmux-header-tools" onPointerEnter={onPointerEnter}>
       {worktree && <WorktreePill worktree={worktree} onApply={onApplyWorktree} onRemove={onRemoveWorktree} />}
-      {pullRequest && <PullRequestChip pullRequest={pullRequest} onMerge={onMergePullRequest} />}
+      {pullRequest && pullRequestChip !== false && (
+        <PullRequestChip pullRequest={pullRequest} onMerge={onMergePullRequest} />
+      )}
       {buttons ? (
         <div className="acpmux-header-tool-group acpmux-header-tool-group-actions">
           {onCustomize ? (

webviews/src/agent-session/acpmux/subagents/SubagentPaneFooter.tsx

@@ -0,0 +1,10 @@
+// A subagent's own pane ends in one quiet line where the chat's composer would be: the pane shows
+// the subagent read only, and the chat it belongs to takes messages. The pane is a tab on the
+// chat's session (subagents/subagentPanes.ts), so a composer there drew the chat's queue and pull
+// request bars and sent its prompts to the chat (Leo 2026-10-20).
+import { useT } from "../i18n";
+
+export function SubagentPaneFooter({ chat }: { chat: string }) {
+  const t = useT();
+  return <p className="cv-subagent-pane-footer">{t("subagents.paneReadOnly", { name: chat })}</p>;
+}

webviews/src/agent-session/acpmux/subagents/subagents.css

@@ -411,3 +411,14 @@ button.cv-subagent > :last-child {
   font-size: var(--text-detail);
   font-variant-numeric: tabular-nums;
 }
+/* A subagent's own pane: where the chat's composer would be, the line naming the chat that takes
+   messages (SubagentPaneFooter.tsx). */
+.cv-subagent-pane-footer {
+  margin: 0;
+  padding: 12px 16px;
+  font-family: var(--cv-font);
+  font-size: var(--text-detail);
+  color: var(--cv-text-muted);
+  text-align: center;
+  user-select: none;
+}

webviews/test/subagent-pane-own-state.test.ts

@@ -0,0 +1,199 @@
+// l10n-allow-file: test fixture prompts, replies and subagent names, not shipped UI.
+// A subagent's own pane (a tab on the chat's session that opens on `subagent:<id>`,
+// subagents/subagentPanes.ts) shows the subagent, read only. It never draws the chat's composer,
+// queue or pull request bars: they are the chat's, and a prompt typed there went to the chat.
+// Leo 2026-10-20: a reviewer's pane showed the chat's queued "this is a bit spammy" and its #663
+// bar. The chat's own pane keeps all of them. The page is the pane's dev entry with its browser
+// host, talking JSON-RPC to a stand-in acpmux daemon; the app's `subagent:` reveal is the page
+// bridge's `revealTurn`.
+//
+// Real Chromium from Playwright; CI fails the file when it cannot launch (requireBrowserLane).
+import { afterAll, beforeAll, describe, expect, setDefaultTimeout, test } from "bun:test";
+import path from "node:path";
+import { chromium, type Browser, type Page } from "playwright";
+import { requireBrowserLane } from "./support/requireBrowserLane";
+import { warmViteServer } from "./support/warmDevServer";
+
+await requireBrowserLane("subagent-pane-own-state.test.ts", async () => {
+  setDefaultTimeout(120_000);
+  try {
+    await (await chromium.launch({ headless: true })).close();
+  } catch {
+    console.warn("subagent-pane-own-state: skipping (run `bunx playwright install chromium`)");
+    describe.skip("subagent pane state", () => test("chromium", () => {}));
+    return;
+  }
+  const { createServer } = await import("vite");
+  const webviews = path.resolve(import.meta.dir, "..");
+
+  const CHAT = "0190a000-0000-7000-8000-0000000000e1";
+  const START = Date.now() - 60_000;
+  const update = (update: Record<string, unknown>, meta?: Record<string, unknown>) => ({
+    method: "session/update",
+    params: { sessionId: "agent-1", update, ...(meta ? { _meta: { acpmux: meta } } : {}) },
+  });
+  type Step = [dir: string, kind: string, msg: Record<string, unknown>];
+  const command = 'gh pr create --title "Add retry"';
+  // A turn that opened a pull request, started a reviewer and still works, with a prompt queued
+  // behind it.
+  const steps: Step[] = [
+    ["mux", "user_message", { text: "Open the PR and have an agent review it" }],
+    ["mux", "turn_started", {}],
+    [
+      "in",
+      "tool_call",
+      update({
+        sessionUpdate: "tool_call",
+        toolCallId: "t1",
+        title: command,
+        kind: "execute",
+        status: "in_progress",
+        rawInput: { command },
+      }),
+    ],
+    [
+      "in",
+      "tool_call_update",
+      update({
+        sessionUpdate: "tool_call_update",
+        toolCallId: "t1",
+        status: "completed",
+        content: [{ type: "content", content: { type: "text", text: "https://github.com/acme/uploader/pull/663" } }],
+        rawOutput: { exit_code: 0 },
+      }),
+    ],
+    [
+      "in",
+      "subagent_spawned",
+      update(
+        { sessionUpdate: "subagent_spawned" },
+        { subagents: [{ id: "a1", parent: null, name: "Reviewer", state: "running", startedAt: START + 4000 }] },
+      ),
+    ],
+    [
+      "in",
+      "agent_message_chunk",
+      update({ sessionUpdate: "agent_message_chunk", content: { type: "text", text: "The reviewer is on it." } }),
+    ],
+    ["mux", "queued", { text: "this is a bit spammy", promptId: "q1", position: 1 }],
+  ];
+  const events = steps.map(([dir, kind, msg], index) => ({
+    sessionId: CHAT,
+    seq: index + 1,
+    at: START + (index + 1) * 1000,
+    dir,
+    kind,
+    msg,
+  }));
+  const session = {
+    sessionId: CHAT,
+    cwd: "/home/dev/uploader",
+    title: "Release review",
+    harness: "claude",
+    family: "claude",
+    status: "working",
+    turnCount: 1,
+    // acpmux's list holds the queue; the replayed `queued` record gives the prompt's whole text.
+    queue: [{ promptId: "q1", prompt: "this is a bit spammy" }],
+    updatedAt: START,
+  };
+
+  function answer(method: string): unknown {
+    switch (method) {
+      case "initialize":
+        return { protocolVersion: 1, _meta: { acpmux: { origin: "local", extensions: [], operations: [] } } };
+      case "_acpmux/watch":
+        return { sessions: [session] };
+      case "_acpmux/attach":
+        return { session, lastSeq: steps.length, events };
+      case "_acpmux/events":
+        return { events: [], hasMore: false, lastSeq: 0 };
+      default:
+        return null;
+    }
+  }
+
+  let daemon: ReturnType<typeof Bun.serve> | undefined;
+  let vite: Awaited<ReturnType<typeof createServer>> | undefined;
+  let browser: Browser | undefined;
+  const open = async (): Promise<Page> => {
+    const { port } = vite!.httpServer!.address() as { port: number };
+    const endpoint = `ws://127.0.0.1:${daemon!.port}/`;
+    const page = await browser!.newPage({ viewport: { width: 900, height: 760 } });
+    await page.goto(`http://127.0.0.1:${port}/#endpoint=${encodeURIComponent(endpoint)}&token=t&session=${CHAT}`);
+    await page.getByText("The reviewer is on it.").waitFor({ timeout: 25_000 });
+    return page;
+  };
+  /// What the pane's bottom shows: the chat's composer, its queued prompt and its pull request bar.
+  const bottom = (page: Page) =>
+    page.evaluate(() => ({
+      composer: document.querySelectorAll(".acpmux-composer").length,
+      queued: [...document.querySelectorAll(".acpmux-queued")].map((row) => row.textContent ?? ""),
+      prDock: document.querySelectorAll(".acpmux-pr-dock").length,
+      readOnly: document.querySelector(".cv-subagent-pane-footer")?.textContent?.trim() ?? "",
+    }));
+  beforeAll(async () => {
+    daemon = Bun.serve({
+      port: 0,
+      hostname: "127.0.0.1",
+      fetch(request, server) {
+        return server.upgrade(request, { data: undefined }) ? undefined : new Response("acpmux", { status: 426 });
+      },
+      websocket: {
+        message(ws, raw) {
+          const message = JSON.parse(String(raw)) as { id?: number; method: string };
+          if (message.id !== undefined)
+            ws.send(JSON.stringify({ jsonrpc: "2.0", id: message.id, result: answer(message.method) }));
+        },
+      },
+    });
+    vite = await createServer({
+      configFile: path.join(webviews, "vite.config.acpmux-pane.mjs"),
+      server: { port: 0, host: "127.0.0.1", strictPort: false },
+      logLevel: "error",
+    });
+    await vite.listen();
+    await warmViteServer(vite, "/");
+    browser = await chromium.launch({ headless: true });
+  });
+  afterAll(async () => {
+    await browser?.close();
+    await vite?.close();
+    await daemon?.stop(true);
+  });
+
+  test("the chat's own pane keeps its composer, its queue and its pull request bar", async () => {
+    const page = await open();
+    await page.locator(".acpmux-queued").first().waitFor({ timeout: 10_000 });
+    const shown = await bottom(page);
+    expect(shown.composer).toBe(1);
+    expect(shown.queued.some((text) => text.includes("this is a bit spammy"))).toBe(true);
+    expect(shown.prDock).toBe(1);
+    expect(shown.readOnly).toBe("");
+    await page.close();
+  });
+
+  test("a subagent's pane shows the subagent read only, with none of the chat's queue or bars", async () => {
+    const page = await open();
+    await page.locator(".acpmux-queued").first().waitFor({ timeout: 10_000 });
+    await page.evaluate(() =>
+      (window as { cmuxAcpmuxBridge?: { revealTurn?(value: string): void } }).cmuxAcpmuxBridge?.revealTurn?.(
+        "subagent:a1",
+      ),
+    );
+    await page.locator(".cv-subagent-of").waitFor({ timeout: 10_000 });
+    const shown = await bottom(page);
+    expect(shown.composer).toBe(0);
+    expect(shown.queued).toEqual([]);
+    expect(shown.prDock).toBe(0);
+    expect(shown.readOnly).toContain("Release review");
+    // "Subagent of" shows the chat in this pane: the chat's composer, queue and bar are back.
+    await page.locator(".cv-subagent-of__pill").click();
+    await page.locator(".acpmux-queued").first().waitFor({ timeout: 10_000 });
+    const chat = await bottom(page);
+    expect(chat.composer).toBe(1);
+    expect(chat.prDock).toBe(1);
+    expect(chat.readOnly).toBe("");
+    await page.close();
+  });
+});