fix(extension): fail closed on borrow confirmation

apps/extension/src/content/BorrowConfirmationOverlay.tsx

@@ -67,8 +67,8 @@ function BorrowRequestItem({ request, isModal }: { request: BorrowRequestData; i
   const totalSeconds = Math.ceil(request.timeoutMs / 1000);
   const [secondsLeft, setSecondsLeft] = useState(totalSeconds);
   const [exiting, setExiting] = useState(false);
-  const [awaitingAutoAllow, setAwaitingAutoAllow] = useState(false);
-  const allowedRef = useRef(false);
+  const [awaitingAutoDeny, setAwaitingAutoDeny] = useState(false);
+  const settledRef = useRef(false);
   const onAllowRef = useRef(request.onAllow);
   const onDenyRef = useRef(request.onDeny);
   onAllowRef.current = request.onAllow;
@@ -76,8 +76,8 @@ function BorrowRequestItem({ request, isModal }: { request: BorrowRequestData; i
 
   useEffect(() => {
     if (secondsLeft <= 0) {
-      if (!allowedRef.current) {
-        setAwaitingAutoAllow(true);
+      if (!settledRef.current) {
+        setAwaitingAutoDeny(true);
       }
       return;
     }
@@ -86,9 +86,9 @@ function BorrowRequestItem({ request, isModal }: { request: BorrowRequestData; i
   }, [secondsLeft]);
 
   function triggerAllow() {
-    if (allowedRef.current) return;
-    allowedRef.current = true;
-    setAwaitingAutoAllow(false);
+    if (settledRef.current) return;
+    settledRef.current = true;
+    setAwaitingAutoDeny(false);
     setExiting(true);
     setTimeout(() => onAllowRef.current(), EXIT_ANIMATION_MS);
   }
@@ -98,9 +98,9 @@ function BorrowRequestItem({ request, isModal }: { request: BorrowRequestData; i
   }
 
   function handleDeny() {
-    if (allowedRef.current) return;
-    allowedRef.current = true;
-    setAwaitingAutoAllow(false);
+    if (settledRef.current) return;
+    settledRef.current = true;
+    setAwaitingAutoDeny(false);
     setExiting(true);
     setTimeout(() => onDenyRef.current(), EXIT_ANIMATION_MS);
   }
@@ -128,13 +128,13 @@ function BorrowRequestItem({ request, isModal }: { request: BorrowRequestData; i
             progress={progress}
             seconds={secondsLeft}
             onProgressTransitionEnd={(propertyName) => {
-              if (!awaitingAutoAllow || secondsLeft !== 0) return;
+              if (!awaitingAutoDeny || secondsLeft !== 0) return;
               if (propertyName !== "stroke-dashoffset") return;
-              triggerAllow();
+              handleDeny();
             }}
           />
           <span className="text-[13px] text-gray-500">
-            {t("borrowConfirmation.autoAllow", { count: secondsLeft })}
+            {t("borrowConfirmation.autoDeny", { count: secondsLeft })}
           </span>
         </div>
         <ActionButtons onDeny={handleDeny} onAllow={handleAllow} />
@@ -156,9 +156,9 @@ function BorrowRequestItem({ request, isModal }: { request: BorrowRequestData; i
       <BorrowProgressBar
         progress={progress}
         onProgressTransitionEnd={(event) => {
-          if (!awaitingAutoAllow || secondsLeft !== 0) return;
+          if (!awaitingAutoDeny || secondsLeft !== 0) return;
           if (event.propertyName !== "width") return;
-          triggerAllow();
+          handleDeny();
         }}
       />
       <ActionButtons onDeny={handleDeny} onAllow={handleAllow} gapClass="gap-2" />

apps/extension/src/content/__tests__/BorrowConfirmationOverlay.test.tsx

@@ -12,7 +12,7 @@ describe("BorrowConfirmationOverlay", () => {
     vi.useRealTimers();
   });
 
-  it("auto-allows after countdown reaches zero and progress transition ends", async () => {
+  it("auto-denies after countdown reaches zero and progress transition ends", async () => {
     const onAllow = vi.fn();
     const onDeny = vi.fn();
 
@@ -37,7 +37,7 @@ describe("BorrowConfirmationOverlay", () => {
         await vi.advanceTimersByTimeAsync(1000);
       });
     }
-    expect(screen.getByText("0 秒后自动允许")).toBeTruthy();
+    expect(screen.getByText("0 秒后自动拒绝")).toBeTruthy();
     await act(async () => {
       await vi.advanceTimersByTimeAsync(1000);
     });
@@ -54,8 +54,8 @@ describe("BorrowConfirmationOverlay", () => {
     await act(async () => {
       await vi.advanceTimersByTimeAsync(150);
     });
-    expect(onAllow).toHaveBeenCalledTimes(1);
-    expect(onDeny).not.toHaveBeenCalled();
+    expect(onDeny).toHaveBeenCalledTimes(1);
+    expect(onAllow).not.toHaveBeenCalled();
   });
 
   it("only invokes onDeny once when deny is clicked repeatedly", async () => {

apps/extension/src/tools/__tests__/borrow-confirmation.test.ts

@@ -162,6 +162,22 @@ describe("requestBorrowConfirmation", () => {
     expect(await pending).toBe(false);
   });
 
+  it("denies malformed or missing confirmation responses", async () => {
+    tabs.get.mockResolvedValue({ id: 42, title: "Tab" });
+    windows.getLastFocused.mockResolvedValue(
+      userWindowWithActiveTab({ windowId: 11, tabId: 42, url: "https://app.example/" }),
+    );
+
+    for (const response of [undefined, {}, { allowed: true }, { type: "borrow-response" }]) {
+      tabs.sendMessage.mockResolvedValueOnce(response);
+      const pending = requestBorrowConfirmation(42, {
+        deps: { tabs, windows, notifications },
+      });
+      await vi.runAllTimersAsync();
+      expect(await pending).toBe(false);
+    }
+  });
+
   it("skips the Agent Window when it is lastFocusedWindow and falls back to a real user window", async () => {
     tabs.get.mockResolvedValueOnce({
       id: 42,
@@ -250,7 +266,7 @@ describe("requestBorrowConfirmation", () => {
     expect(tabs.sendMessage.mock.calls[1]?.[0]).toBe(301);
   });
 
-  it("does NOT fail-open immediately when every candidate's sendMessage fails — waits for notification button or timeout", async () => {
+  it("waits for a notification decision and denies when every UI path times out", async () => {
     const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => undefined);
     tabs.get.mockResolvedValueOnce({ id: 42, title: "Tab" });
     windows.getLastFocused.mockResolvedValueOnce(
@@ -282,13 +298,13 @@ describe("requestBorrowConfirmation", () => {
 
     expect(tabs.sendMessage).toHaveBeenCalledTimes(2);
     // CRITICAL: previously this would already be settled(true). Now we
-    // require an explicit user choice (notification button) or timeout.
+    // require an explicit user choice (notification button) or safe timeout.
     expect(resolved).toBe(false);
 
-    // Allow the BACKGROUND_TIMEOUT_MS fail-open to fire so the test resolves.
+    // The background timeout must resolve the request without authorizing it.
     await vi.advanceTimersByTimeAsync(BACKGROUND_TIMEOUT_MS);
-    expect(await pending).toBe(true);
-    expect(resolvedValue).toBe(true);
+    expect(await pending).toBe(false);
+    expect(resolvedValue).toBe(false);
 
     const exhaustedWarn = warnSpy.mock.calls.find(
       (call) =>
@@ -375,7 +391,7 @@ describe("requestBorrowConfirmation", () => {
     expect(await pending).toBe(false);
   });
 
-  it("fail-opens when no injectable user window exists at all", async () => {
+  it("denies when no injectable user window exists at all", async () => {
     tabs.get.mockResolvedValueOnce({ id: 42, title: "Stranded Tab" });
     windows.getLastFocused.mockResolvedValueOnce(
       userWindowWithActiveTab({ windowId: 500, tabId: 5001, url: "about:blank" }),
@@ -394,7 +410,7 @@ describe("requestBorrowConfirmation", () => {
     });
     await vi.runAllTimersAsync();
 
-    expect(await pending).toBe(true);
+    expect(await pending).toBe(false);
     expect(tabs.sendMessage).not.toHaveBeenCalled();
     // No notification either — there's no actionable target window.
     expect(notifications.create).not.toHaveBeenCalled();
@@ -469,7 +485,7 @@ describe("requestBorrowConfirmation", () => {
     await pending;
   });
 
-  it("fail-opens after background timeout when content script never responds", async () => {
+  it("denies after background timeout when content script never responds", async () => {
     tabs.get.mockResolvedValueOnce({ id: 42, title: "Tab" });
     windows.getLastFocused.mockResolvedValueOnce(
       userWindowWithActiveTab({ windowId: 11, tabId: 42, url: "https://app.example/" }),
@@ -480,10 +496,10 @@ describe("requestBorrowConfirmation", () => {
       deps: { tabs, windows, notifications },
     });
     await vi.advanceTimersByTimeAsync(BACKGROUND_TIMEOUT_MS);
-    expect(await pending).toBe(true);
+    expect(await pending).toBe(false);
   });
 
-  it("dismisses pending overlay and fail-opens when aborted", async () => {
+  it("dismisses the pending overlay and denies when aborted", async () => {
     tabs.get.mockResolvedValueOnce({ id: 42, title: "Borrow Target" });
     windows.getLastFocused.mockResolvedValueOnce(
       userWindowWithActiveTab({ windowId: 11, tabId: 7, url: "https://app.example/" }),
@@ -500,7 +516,7 @@ describe("requestBorrowConfirmation", () => {
     controller.abort();
     await vi.runAllTimersAsync();
 
-    expect(await pending).toBe(true);
+    expect(await pending).toBe(false);
     expect(tabs.sendMessage).toHaveBeenCalledTimes(2);
     const requestMessage = tabs.sendMessage.mock.calls[0][1] as { requestId: string };
     const cancelMessage = tabs.sendMessage.mock.calls[1][1] as {

apps/extension/src/tools/borrow-confirmation.ts

@@ -114,9 +114,8 @@ const pendingBorrowNotifications = new Map<string, PendingBorrowNotification>();
  *
  * This is the *fallback* authorization path that fires when no candidate
  * user window could host the in-page overlay (every `chrome.tabs.sendMessage`
- * was rejected because the content script was not present). Without it the
- * background-task fail-open at the end of `tryCandidate` would silently
- * allow the borrow without any user-visible authorization step.
+ * was rejected because the content script was not present). It preserves an
+ * explicit authorization path without weakening the fail-closed timeout.
  */
 const pendingBorrowDecisions = new Map<string, (allowed: boolean) => void>();
 
@@ -170,7 +169,7 @@ export function attachBorrowNotificationClickHandler(deps: {
  * Allow / Deny buttons on the OS notification can resolve the matching
  * pending `requestBorrowConfirmation`. This is the explicit-authorization
  * fallback path used when every candidate user window's content script was
- * missing — without it we'd be back to silently fail-opening the borrow.
+ * missing.
  *
  * Button index convention (matches `BorrowNotificationCopy`):
  *   - 0 → Allow → `resolve(true)`
@@ -326,8 +325,7 @@ async function listConfirmationCandidates(
     if (typeof w.id !== "number") continue;
     // Never bounce the overlay back into a session's Agent Window — those
     // pages can't host a content script when they're on the about:blank
-    // bootstrap URL, so sendMessage would fail-open and silently allow the
-    // borrow with no UI shown.
+    // bootstrap URL, so they cannot surface an authorization decision.
     if (isAgentWindowId(w.id)) continue;
     const activeTab = w.tabs?.find((t) => t.active === true) ?? null;
     if (!activeTab || typeof activeTab.id !== "number") continue;
@@ -360,16 +358,14 @@ async function listConfirmationCandidates(
  * *explicit-authorization fallback* when every candidate fails sendMessage:
  * we no longer silently allow the borrow in that case, the promise stays
  * pending until the user clicks a notification button (resolves true/false)
- * or `BACKGROUND_TIMEOUT_MS` fires (last-resort fail-open so the agent
- * doesn't hang forever when even the notification path is broken).
+ * or `BACKGROUND_TIMEOUT_MS` fires and safely denies the request.
  *
  * Clicking the notification body (vs. its buttons) focuses the chosen user
  * window so the overlay becomes visible — the previous behaviour.
  *
- * Returns `true` on user-allow (overlay or notification) OR last-resort
- * fail-open (no candidate window at all; abort signal; timeout). Returns
- * `false` only on explicit user-deny (overlay button or notification Deny
- * button).
+ * Returns `true` only on an explicit user allow from the overlay or
+ * notification. Missing UI, aborts, malformed responses, and timeouts all
+ * fail closed and return `false`.
  */
 export async function requestBorrowConfirmation(
   tabId: number,
@@ -385,12 +381,9 @@ export async function requestBorrowConfirmation(
 
   // The borrow pipeline already fetched this tab moments earlier
   // (validateBorrowTarget in tabs.ts), so a failure here is a transient
-  // SW/page hiccup, not a missing tab. Do NOT fail-open: silently allowing
-  // a borrow with no confirmation UI contradicts the gate's purpose and is
-  // not one of the documented fail-open cases (no candidate window; abort;
-  // timeout — see this function's doc comment). Fall back to a generic
-  // title and still surface the overlay + notification so the user gets a
-  // real chance to approve or deny.
+  // SW/page hiccup, not a missing tab. Fall back to a generic title and still
+  // surface the overlay + notification so the user gets a real chance to
+  // approve or deny.
   let tabTitle: string;
   try {
     const tab = await tabsApi.get(tabId);
@@ -405,10 +398,10 @@ export async function requestBorrowConfirmation(
 
   const candidates = await listConfirmationCandidates(windowsApi, isAgentWindowId);
   if (candidates.length === 0) {
-    console.warn("[bsk borrow] no injectable user window available — proceeding without overlay", {
+    console.warn("[bsk borrow] no injectable user window available — denying borrow", {
       tabId,
     });
-    return true;
+    return false;
   }
 
   const requestId = createBorrowRequestId(tabId);
@@ -419,7 +412,7 @@ export async function requestBorrowConfirmation(
   // overlay immediately.
   const notificationAnchor = candidates[0];
   if (!notificationAnchor) {
-    return true;
+    return false;
   }
 
   return new Promise<boolean>((resolve) => {
@@ -463,7 +456,7 @@ export async function requestBorrowConfirmation(
           });
         });
       }
-      settle(true);
+      settle(false);
     };
 
     if (signal?.aborted) {
@@ -473,19 +466,17 @@ export async function requestBorrowConfirmation(
     signal?.addEventListener("abort", onAbort, { once: true });
 
     timeout = setTimeout(() => {
-      console.info("[bsk borrow] confirmation timed out — proceeding", {
+      console.info("[bsk borrow] confirmation timed out — denying borrow", {
         tabId,
         messageTabId: activeMessageTabId,
       });
-      settle(true);
+      settle(false);
     }, BACKGROUND_TIMEOUT_MS);
 
     // Surface the OS notification *before* messaging any candidate so the
     // user has a parallel signal even if every content script is missing.
     // The Allow / Deny buttons let the user authorize explicitly when the
-    // in-page overlay never reached them — without those buttons we'd have
-    // to fail-open after `tryCandidate` exhausts its candidates, which is
-    // exactly the silent-allow bug we're fixing here.
+    // in-page overlay never reached them.
     if (notificationsApi) {
       pendingBorrowNotifications.set(notificationId, {
         windowId: notificationAnchor.windowId,
@@ -499,7 +490,7 @@ export async function requestBorrowConfirmation(
           title: copy.title,
           message: copy.body(tabTitle),
           priority: 2,
-          requireInteraction: false,
+          requireInteraction: true,
           silent: false,
           buttons: [{ title: copy.allowButton }, { title: copy.denyButton }],
         })
@@ -523,15 +514,12 @@ export async function requestBorrowConfirmation(
     ): void => {
       if (settled) return;
       if (index >= candidates.length) {
-        // Every candidate rejected sendMessage. We deliberately do NOT
-        // fail-open here anymore: silently allowing a borrow with zero
-        // user-visible authorization UI is the bug. Instead we keep the
-        // promise pending and rely on:
+        // Every candidate rejected sendMessage. Keep the promise pending and
+        // rely on:
         //   • the OS notification's Allow / Deny buttons for an explicit
         //     user choice (preferred), or
-        //   • the BACKGROUND_TIMEOUT_MS fail-open as the last-resort
-        //     soft-fail so the agent doesn't hang forever when even the
-        //     notification API is unavailable.
+        //   • the BACKGROUND_TIMEOUT_MS fail-closed result so the agent does
+        //     not hang forever when even the notification API is unavailable.
         // Keep the diagnostics so real-world frequency is still observable.
         console.warn(
           "[bsk borrow] every candidate user window failed sendMessage — awaiting notification button or timeout",
@@ -560,7 +548,9 @@ export async function requestBorrowConfirmation(
         .sendMessage(candidate.tabId, message)
         .then((response) => {
           if (settled) return;
-          const allowed = (response as BorrowResponseMessage | undefined)?.allowed !== false;
+          const candidateResponse = response as BorrowResponseMessage | undefined;
+          const allowed =
+            candidateResponse?.type === "borrow-response" && candidateResponse.allowed === true;
           console.info("[bsk borrow] confirmation response", { tabId, allowed });
           settle(allowed);
         })

packages/i18n/src/locales/en-US/extension.json

@@ -52,7 +52,7 @@
     "titleInactive": "Agent wants to borrow a tab",
     "body": "An AI agent wants to move this tab into its workspace. You can deny or allow the borrow.",
     "targetTab": "Target tab:",
-    "autoAllow": "Auto-allowing in {{count}}s",
+    "autoDeny": "Request expires in {{count}}s",
     "deny": "Deny",
     "allow": "Allow",
     "notificationTitle": "BrowserSkill: Agent wants to borrow a tab",

packages/i18n/src/locales/zh-CN/extension.json

@@ -52,7 +52,7 @@
     "titleInactive": "Agent 请求借用标签页",
     "body": "AI Agent 希望将此标签页移入工作区。您可以拒绝或允许借用。",
     "targetTab": "目标标签页：",
-    "autoAllow": "{{count}} 秒后自动允许",
+    "autoDeny": "{{count}} 秒后自动拒绝",
     "deny": "拒绝",
     "allow": "允许",
     "notificationTitle": "BrowserSkill：Agent 请求借用标签页",