Fix sticky Chrome MCP status probes

# Conflicts:
#	extensions/browser/src/browser/chrome-mcp.ts
#	extensions/browser/src/browser/server-context.ts

extensions/browser/src/browser/chrome-mcp.test.ts

@@ -2,6 +2,7 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import {
   clickChromeMcpElement,
   buildChromeMcpArgs,
+  ensureChromeMcpAvailable,
   evaluateChromeMcpScript,
   listChromeMcpTabs,
   navigateChromeMcpPage,
@@ -186,6 +187,72 @@ describe("chrome MCP page parsing", () => {
     expect(result).toBe(123);
   });
 
+  it("does not cache an ephemeral availability probe before the next real attach", async () => {
+    let factoryCalls = 0;
+    const closeMocks: Array<ReturnType<typeof vi.fn>> = [];
+    const factory: ChromeMcpSessionFactory = async () => {
+      factoryCalls += 1;
+      const session = createFakeSession();
+      const closeMock = vi.fn().mockResolvedValue(undefined);
+      session.client.close = closeMock as typeof session.client.close;
+      closeMocks.push(closeMock);
+      return session;
+    };
+    setChromeMcpSessionFactoryForTest(factory);
+
+    await ensureChromeMcpAvailable("chrome-live", undefined, { ephemeral: true });
+
+    expect(factoryCalls).toBe(1);
+    expect(closeMocks[0]).toHaveBeenCalledTimes(1);
+
+    const tabs = await listChromeMcpTabs("chrome-live");
+
+    expect(factoryCalls).toBe(2);
+    expect(closeMocks[1]).not.toHaveBeenCalled();
+    expect(tabs).toHaveLength(2);
+  });
+
+  it("does not poison the next real attach after an ephemeral no-page probe", async () => {
+    let factoryCalls = 0;
+    const closeMocks: Array<ReturnType<typeof vi.fn>> = [];
+    const factory: ChromeMcpSessionFactory = async () => {
+      factoryCalls += 1;
+      const session = createFakeSession();
+      const closeMock = vi.fn().mockResolvedValue(undefined);
+      session.client.close = closeMock as typeof session.client.close;
+      closeMocks.push(closeMock);
+      if (factoryCalls === 1) {
+        const callTool = vi.fn(async ({ name }: ToolCall) => {
+          if (name === "list_pages") {
+            return {
+              content: [{ type: "text", text: "No page selected" }],
+              isError: true,
+            };
+          }
+          throw new Error(`unexpected tool ${name}`);
+        });
+        session.client.callTool = callTool as typeof session.client.callTool;
+      }
+      return session;
+    };
+    setChromeMcpSessionFactoryForTest(factory);
+
+    await expect(
+      listChromeMcpTabs("chrome-live", undefined, {
+        ephemeral: true,
+      }),
+    ).rejects.toThrow(/No page selected/);
+
+    expect(factoryCalls).toBe(1);
+    expect(closeMocks[0]).toHaveBeenCalledTimes(1);
+
+    const tabs = await listChromeMcpTabs("chrome-live");
+
+    expect(factoryCalls).toBe(2);
+    expect(closeMocks[1]).not.toHaveBeenCalled();
+    expect(tabs).toHaveLength(2);
+  });
+
   it("surfaces MCP tool errors instead of JSON parse noise", async () => {
     const factory: ChromeMcpSessionFactory = async () => {
       const session = createFakeSession();

extensions/browser/src/browser/chrome-mcp.ts

@@ -31,6 +31,18 @@ type ChromeMcpSession = {
   ready: Promise<void>;
 };
 
+type ChromeMcpCallOptions = {
+  ephemeral?: boolean;
+  timeoutMs?: number;
+  signal?: AbortSignal;
+};
+
+type ChromeMcpSessionLease = {
+  session: ChromeMcpSession;
+  cacheKey: string;
+  temporary: boolean;
+};
+
 type ChromeMcpSessionFactory = (
   profileName: string,
   userDataDir?: string,
@@ -332,7 +344,42 @@ async function createRealSession(
   };
 }
 
-async function getSession(profileName: string, userDataDir?: string): Promise<ChromeMcpSession> {
+async function waitForChromeMcpReady(
+  session: ChromeMcpSession,
+  profileName: string,
+  timeoutMs?: number,
+): Promise<void> {
+  if (!timeoutMs || timeoutMs <= 0) {
+    await session.ready;
+    return;
+  }
+
+  let timer: ReturnType<typeof setTimeout> | undefined;
+  try {
+    await Promise.race([
+      session.ready,
+      new Promise<never>((_, reject) => {
+        timer = setTimeout(() => {
+          reject(
+            new BrowserProfileUnavailableError(
+              `Chrome MCP existing-session attach for profile "${profileName}" timed out after ${timeoutMs}ms.`,
+            ),
+          );
+        }, timeoutMs);
+      }),
+    ]);
+  } finally {
+    if (timer) {
+      clearTimeout(timer);
+    }
+  }
+}
+
+async function getSession(
+  profileName: string,
+  userDataDir?: string,
+  timeoutMs?: number,
+): Promise<ChromeMcpSession> {
   const cacheKey = buildChromeMcpSessionCacheKey(profileName, userDataDir);
   await closeChromeMcpSessionsForProfile(profileName, cacheKey);
 
@@ -364,7 +411,7 @@ async function getSession(profileName: string, userDataDir?: string): Promise<Ch
     }
   }
   try {
-    await session.ready;
+    await waitForChromeMcpReady(session, profileName, timeoutMs);
     return session;
   } catch (err) {
     const current = sessions.get(cacheKey);
@@ -375,23 +422,110 @@ async function getSession(profileName: string, userDataDir?: string): Promise<Ch
   }
 }
 
+async function getExistingSession(
+  cacheKey: string,
+  profileName: string,
+  timeoutMs?: number,
+): Promise<ChromeMcpSession | null> {
+  let session = sessions.get(cacheKey);
+  if (session && session.transport.pid === null) {
+    sessions.delete(cacheKey);
+    session = undefined;
+  }
+  if (session) {
+    try {
+      await waitForChromeMcpReady(session, profileName, timeoutMs);
+      return session;
+    } catch (err) {
+      const current = sessions.get(cacheKey);
+      if (current?.transport === session.transport) {
+        sessions.delete(cacheKey);
+      }
+      throw err;
+    }
+  }
+
+  const pending = pendingSessions.get(cacheKey);
+  if (!pending) {
+    return null;
+  }
+
+  session = await pending;
+  try {
+    await waitForChromeMcpReady(session, profileName, timeoutMs);
+    return session;
+  } catch (err) {
+    const current = sessions.get(cacheKey);
+    if (current?.transport === session.transport) {
+      sessions.delete(cacheKey);
+    }
+    throw err;
+  }
+}
+
+async function createEphemeralSession(
+  profileName: string,
+  userDataDir?: string,
+  timeoutMs?: number,
+): Promise<ChromeMcpSession> {
+  const session = await (sessionFactory ?? createRealSession)(profileName, userDataDir);
+  try {
+    await waitForChromeMcpReady(session, profileName, timeoutMs);
+    return session;
+  } catch (err) {
+    await session.client.close().catch(() => {});
+    throw err;
+  }
+}
+
+async function leaseSession(
+  profileName: string,
+  userDataDir?: string,
+  options: ChromeMcpCallOptions = {},
+): Promise<ChromeMcpSessionLease> {
+  const cacheKey = buildChromeMcpSessionCacheKey(profileName, userDataDir);
+  if (!options.ephemeral) {
+    return {
+      session: await getSession(profileName, userDataDir, options.timeoutMs),
+      cacheKey,
+      temporary: false,
+    };
+  }
+
+  // Status probes should avoid seeding the shared attach session cache, but they can safely
+  // reuse a real cached session if one already exists.
+  const existingSession = await getExistingSession(cacheKey, profileName, options.timeoutMs);
+  if (existingSession) {
+    return {
+      session: existingSession,
+      cacheKey,
+      temporary: false,
+    };
+  }
+
+  return {
+    session: await createEphemeralSession(profileName, userDataDir, options.timeoutMs),
+    cacheKey,
+    temporary: true,
+  };
+}
+
 async function callTool(
   profileName: string,
   userDataDir: string | undefined,
   name: string,
   args: Record<string, unknown> = {},
-  opts?: { timeoutMs?: number; signal?: AbortSignal },
+  options: ChromeMcpCallOptions = {},
 ): Promise<ChromeMcpToolResult> {
-  const cacheKey = buildChromeMcpSessionCacheKey(profileName, userDataDir);
-  const timeoutMs = opts?.timeoutMs;
-  const signal = opts?.signal;
+  const timeoutMs = options.timeoutMs;
+  const signal = options.signal;
   if (signal?.aborted) {
     throw signal.reason ?? new Error("aborted");
   }
 
   for (let attempt = 0; attempt < 2; attempt += 1) {
-    const session = await getSession(profileName, userDataDir);
-    const rawCall = session.client.callTool({
+    const lease = await leaseSession(profileName, userDataDir, options);
+    const rawCall = lease.session.client.callTool({
       name,
       arguments: args,
     }) as Promise<ChromeMcpToolResult>;
@@ -430,10 +564,12 @@ async function callTool(
       void rawCall.catch(() => {});
       // Transport/connection error, timeout, or abort: tear down session so it reconnects.
       // Transport-identity check prevents clobbering a replacement session created concurrently.
-      const cur = sessions.get(cacheKey);
-      if (cur?.transport === session.transport) {
-        sessions.delete(cacheKey);
-        await session.client.close().catch(() => {});
+      if (!lease.temporary) {
+        const cur = sessions.get(lease.cacheKey);
+        if (cur?.transport === lease.session.transport) {
+          sessions.delete(lease.cacheKey);
+          await lease.session.client.close().catch(() => {});
+        }
       }
       throw err;
     } finally {
@@ -443,6 +579,9 @@ async function callTool(
       if (signal && abortListener) {
         signal.removeEventListener("abort", abortListener);
       }
+      if (lease.temporary) {
+        await lease.session.client.close().catch(() => {});
+      }
     }
     // Tool-level errors (element not found, script error, etc.) don't indicate a
     // broken connection. A stale selected-page error does poison the Chrome MCP
@@ -450,10 +589,12 @@ async function callTool(
     if (result.isError) {
       const message = extractToolErrorMessage(result, name);
       if (shouldReconnectForToolError(name, message)) {
-        const cur = sessions.get(cacheKey);
-        if (cur?.transport === session.transport) {
-          sessions.delete(cacheKey);
-          await session.client.close().catch(() => {});
+        if (!lease.temporary) {
+          const cur = sessions.get(lease.cacheKey);
+          if (cur?.transport === lease.session.transport) {
+            sessions.delete(lease.cacheKey);
+            await lease.session.client.close().catch(() => {});
+          }
         }
         if (attempt === 0) {
           continue;
@@ -492,8 +633,12 @@ async function findPageById(
 export async function ensureChromeMcpAvailable(
   profileName: string,
   userDataDir?: string,
+  options: ChromeMcpCallOptions = {},
 ): Promise<void> {
-  await getSession(profileName, userDataDir);
+  const lease = await leaseSession(profileName, userDataDir, options);
+  if (lease.temporary) {
+    await lease.session.client.close().catch(() => {});
+  }
 }
 
 export function getChromeMcpPid(profileName: string): number | null {
@@ -519,16 +664,18 @@ export async function stopAllChromeMcpSessions(): Promise<void> {
 export async function listChromeMcpPages(
   profileName: string,
   userDataDir?: string,
+  options: ChromeMcpCallOptions = {},
 ): Promise<ChromeMcpStructuredPage[]> {
-  const result = await callTool(profileName, userDataDir, "list_pages");
+  const result = await callTool(profileName, userDataDir, "list_pages", {}, options);
   return extractStructuredPages(result);
 }
 
 export async function listChromeMcpTabs(
   profileName: string,
   userDataDir?: string,
+  options: ChromeMcpCallOptions = {},
 ): Promise<BrowserTab[]> {
-  return toBrowserTabs(await listChromeMcpPages(profileName, userDataDir));
+  return toBrowserTabs(await listChromeMcpPages(profileName, userDataDir, options));
 }
 
 export async function openChromeMcpTab(

extensions/browser/src/browser/server-context.availability.ts

@@ -90,7 +90,10 @@ export function createProfileAvailability({
 
   const isTransportAvailable = async (timeoutMs?: number) => {
     if (capabilities.usesChromeMcp) {
-      await ensureChromeMcpAvailable(profile.name, profile.userDataDir);
+      await ensureChromeMcpAvailable(profile.name, profile.userDataDir, {
+        ephemeral: true,
+        timeoutMs,
+      });
       return true;
     }
     return await isReachable(timeoutMs);

extensions/browser/src/browser/server-context.existing-session.test.ts

@@ -13,7 +13,7 @@ vi.mock("./chrome-mcp.js", () => ({
   openChromeMcpTab: vi.fn(async () => ({
     targetId: "8",
     title: "",
-    url: "https://openclaw.ai",
+    url: "about:blank",
     type: "page",
   })),
   closeChromeMcpTab: vi.fn(async () => {}),
@@ -101,6 +101,53 @@ describe("browser server-context existing-session profile", () => {
         tabCount: 0,
       }),
     ]);
+
+    expect(chromeMcp.ensureChromeMcpAvailable).toHaveBeenCalledWith(
+      "chrome-live",
+      "/tmp/brave-profile",
+      { ephemeral: true },
+    );
+    expect(chromeMcp.listChromeMcpTabs).toHaveBeenCalledWith("chrome-live", "/tmp/brave-profile", {
+      ephemeral: true,
+    });
+  });
+
+  it("keeps the next real attach on the normal sticky session path after an idle status probe", async () => {
+    fs.mkdirSync("/tmp/brave-profile", { recursive: true });
+    const state = makeState();
+    const ctx = createBrowserRouteContext({ getState: () => state });
+    const live = ctx.forProfile("chrome-live");
+
+    vi.mocked(chromeMcp.listChromeMcpTabs).mockRejectedValueOnce(new Error("No page selected"));
+
+    await expect(ctx.listProfiles()).resolves.toEqual([
+      expect.objectContaining({
+        name: "chrome-live",
+        running: true,
+        tabCount: 0,
+      }),
+    ]);
+
+    vi.mocked(chromeMcp.listChromeMcpTabs).mockClear();
+
+    await live.ensureBrowserAvailable();
+    const tabs = await live.listTabs();
+
+    expect(tabs.map((tab) => tab.targetId)).toEqual(["7"]);
+    expect(chromeMcp.ensureChromeMcpAvailable).toHaveBeenLastCalledWith(
+      "chrome-live",
+      "/tmp/brave-profile",
+    );
+    expect(chromeMcp.listChromeMcpTabs).toHaveBeenNthCalledWith(
+      1,
+      "chrome-live",
+      "/tmp/brave-profile",
+    );
+    expect(chromeMcp.listChromeMcpTabs).toHaveBeenNthCalledWith(
+      2,
+      "chrome-live",
+      "/tmp/brave-profile",
+    );
   });
 
   it("routes tab operations through the Chrome MCP backend", async () => {
@@ -118,22 +165,22 @@ describe("browser server-context existing-session profile", () => {
       ])
       .mockResolvedValueOnce([
         { targetId: "7", title: "", url: "https://example.com", type: "page" },
-        { targetId: "8", title: "", url: "https://openclaw.ai", type: "page" },
+        { targetId: "8", title: "", url: "about:blank", type: "page" },
       ])
       .mockResolvedValueOnce([
         { targetId: "7", title: "", url: "https://example.com", type: "page" },
-        { targetId: "8", title: "", url: "https://openclaw.ai", type: "page" },
+        { targetId: "8", title: "", url: "about:blank", type: "page" },
       ])
       .mockResolvedValueOnce([
         { targetId: "7", title: "", url: "https://example.com", type: "page" },
-        { targetId: "8", title: "", url: "https://openclaw.ai", type: "page" },
+        { targetId: "8", title: "", url: "about:blank", type: "page" },
       ]);
 
     await live.ensureBrowserAvailable();
     const tabs = await live.listTabs();
     expect(tabs.map((tab) => tab.targetId)).toEqual(["7"]);
 
-    const opened = await live.openTab("https://openclaw.ai");
+    const opened = await live.openTab("about:blank");
     expect(opened.targetId).toBe("8");
 
     const selected = await live.ensureTabAvailable();
@@ -149,7 +196,7 @@ describe("browser server-context existing-session profile", () => {
     expect(chromeMcp.listChromeMcpTabs).toHaveBeenCalledWith("chrome-live", "/tmp/brave-profile");
     expect(chromeMcp.openChromeMcpTab).toHaveBeenCalledWith(
       "chrome-live",
-      "https://openclaw.ai",
+      "about:blank",
       "/tmp/brave-profile",
     );
     expect(chromeMcp.focusChromeMcpTab).toHaveBeenCalledWith(

extensions/browser/src/browser/server-context.ts

@@ -3,6 +3,7 @@ import {
   resolveCdpReachabilityPolicy,
 } from "./cdp-reachability-policy.js";
 import { usesFastLoopbackCdpProbeClass } from "./cdp-timeouts.js";
+import { listChromeMcpTabs } from "./chrome-mcp.js";
 import { isChromeReachable, resolveOpenClawUserDataDir } from "./chrome.js";
 import type { ResolvedBrowserProfile } from "./config.js";
 import { resolveProfile } from "./config.js";
@@ -181,7 +182,9 @@ export function createBrowserRouteContext(opts: ContextOptions): BrowserRouteCon
         try {
           running = await profileCtx.isTransportAvailable(300);
           if (running) {
-            const tabs = await profileCtx.listTabs().catch(() => [] as BrowserTab[]);
+            const tabs = await listChromeMcpTabs(profile.name, profile.userDataDir, {
+              ephemeral: true,
+            }).catch(() => [] as BrowserTab[]);
             tabCount = tabs.filter((t) => t.type === "page").length;
           }
         } catch {