diff --git a/apps/web/src/app/__tests__/fallback-poll.test.ts b/apps/web/src/app/__tests__/fallback-poll.test.ts
new file mode 100644
index 0000000..e95128c
--- /dev/null
+++ b/apps/web/src/app/__tests__/fallback-poll.test.ts
@@ -0,0 +1,135 @@
+/**
+ * SSE 的兜底轮询 —— **推送丢了,画面最多旧 10 秒**,不必等人按刷新。
+ *
+ * 这里钉四条:①每个周期把这一屏**在用的**查询重取一遍(挂着观察者的才算在用;
+ * 早已离开的屏留在缓存里的键不碰);②`stop()` 之后定时器真的停了 —— 离开界面不许继续打接口;
+ * ③页签藏起来时不打,回到前台先补一趟;④正在飞的请求不被兜底那一下取消重发(在途去重)。
+ */
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { QueryClient, QueryObserver } from '@tanstack/react-query';
+import { startFallbackPolling } from '../fallback-poll.ts';
+
+type Visibility = {
+  hidden: boolean;
+  fire(): void;
+  addEventListener(type: string, handler: () => void): void;
+  removeEventListener(type: string, handler: () => void): void;
+  readonly listeners: number;
+};
+
+/** 假的 document:只有 hidden 与 visibilitychange 这两样,测试自己拨 */
+function fakeDoc(): Visibility {
+  const handlers = new Set<() => void>();
+  return {
+    hidden: false,
+    fire: () => handlers.forEach((h) => h()),
+    addEventListener: (_type, h) => void handlers.add(h),
+    removeEventListener: (_type, h) => void handlers.delete(h),
+    get listeners() {
+      return handlers.size;
+    },
+  };
+}
+
+/** 一把「在用的」查询:挂一个观察者,像组件 mount 了一样;回报它被取了几次(`delayOf` 按第几次给时延) */
+function mounted(qc: QueryClient, key: readonly unknown[], delayOf: (call: number) => number = () => 0) {
+  let calls = 0;
+  const observer = new QueryObserver(qc, {
+    queryKey: key,
+    queryFn: async () => {
+      calls += 1;
+      const delayMs = delayOf(calls);
+      if (delayMs > 0) await new Promise((r) => setTimeout(r, delayMs));
+      return { n: calls };
+    },
+  });
+  const unsubscribe = observer.subscribe(() => undefined);
+  return { calls: () => calls, unsubscribe };
+}
+
+const flush = async (): Promise<void> => {
+  await vi.advanceTimersByTimeAsync(0);
+};
+
+describe('startFallbackPolling', () => {
+  let qc: QueryClient;
+  beforeEach(() => {
+    vi.useFakeTimers();
+    qc = new QueryClient({ defaultOptions: { queries: { retry: false, staleTime: 5_000 } } });
+  });
+  afterEach(() => {
+    qc.clear();
+    vi.useRealTimers();
+  });
+
+  it('每 10 秒把 desk 下在用的查询各重取一次;别的前缀与没人看的键不碰', async () => {
+    const tasks = mounted(qc, ['desk', 'tasks']);
+    const detail = mounted(qc, ['desk', 'task', 'T1']);
+    const gov = mounted(qc, ['gov', 'tasks']);
+    // 早已离开的屏:缓存里有,没人看
+    qc.setQueryData(['desk', 'task', 'T0'], { stale: true });
+    await flush();
+    expect([tasks.calls(), detail.calls(), gov.calls()]).toEqual([1, 1, 1]); // 首取
+
+    const stop = startFallbackPolling(qc, { intervalMs: 10_000, prefix: ['desk'], doc: fakeDoc() });
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect([tasks.calls(), detail.calls()]).toEqual([2, 2]);
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect([tasks.calls(), detail.calls()]).toEqual([3, 3]);
+    expect(gov.calls()).toBe(1);
+    expect(qc.getQueryState(['desk', 'task', 'T0'])?.fetchStatus).toBe('idle');
+    stop();
+  });
+
+  it('stop() 之后定时器停了,监听也摘了 —— 离开界面不再打接口', async () => {
+    const tasks = mounted(qc, ['desk', 'tasks']);
+    const doc = fakeDoc();
+    await flush();
+    const stop = startFallbackPolling(qc, { intervalMs: 10_000, prefix: ['desk'], doc });
+    expect(doc.listeners).toBe(1);
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect(tasks.calls()).toBe(2);
+
+    stop();
+    expect(doc.listeners).toBe(0);
+    await vi.advanceTimersByTimeAsync(60_000);
+    expect(tasks.calls()).toBe(2);
+  });
+
+  it('页签藏起来时不打;回到前台先补一趟,周期照旧', async () => {
+    const tasks = mounted(qc, ['desk', 'tasks']);
+    const doc = fakeDoc();
+    await flush();
+    const stop = startFallbackPolling(qc, { intervalMs: 10_000, prefix: ['desk'], doc });
+
+    doc.hidden = true;
+    doc.fire();
+    await vi.advanceTimersByTimeAsync(30_000);
+    expect(tasks.calls()).toBe(1);
+
+    doc.hidden = false;
+    doc.fire();
+    await flush();
+    expect(tasks.calls()).toBe(2); // 回前台立刻补一趟
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect(tasks.calls()).toBe(3);
+    stop();
+  });
+
+  it('上一趟还在飞,兜底这一下不取消它重发 —— 慢接口不会被兜底打成永远取不回', async () => {
+    /*
+     * 首取要先回来:TanStack 只对**已有数据**的查询做 cancelRefetch(首取飞着时谁都不掐),
+     * 所以「第二趟慢」才是有分辨力的局面 —— 第一版拿首取当慢趟,true/false 都过。
+     */
+    const slow = mounted(qc, ['desk', 'tasks'], (call) => (call === 1 ? 0 : 25_000));
+    await flush();
+    expect(slow.calls()).toBe(1);
+    const stop = startFallbackPolling(qc, { intervalMs: 10_000, prefix: ['desk'], doc: fakeDoc() });
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect(slow.calls()).toBe(2); // 第二趟起飞,要 25 秒
+    await vi.advanceTimersByTimeAsync(10_000);
+    // 第二趟还没回来:这一个兜底周期不该把它取消再发(cancelRefetch:true 会让这里变成 3)
+    expect(slow.calls()).toBe(2);
+    stop();
+  });
+});
diff --git a/apps/web/src/app/app-shell.tsx b/apps/web/src/app/app-shell.tsx
index e0fb1ae..ff19ffa 100644
--- a/apps/web/src/app/app-shell.tsx
+++ b/apps/web/src/app/app-shell.tsx
@@ -6,7 +6,7 @@
  *
  * **前端零过程状态**:数据全部来自服务端投影,刷新即从投影重建(§9.2)。
  */
-import { useRef, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
 import type { Principal, TaskCard, TaskDetail, WorkOrderReply } from '@contracts';
 import {
@@ -28,6 +28,7 @@ import { call } from '@web-shared/typed-fetch.ts';
 import { logout as kcLogout } from '@web-shared/auth.ts';
 import { useChatWidth } from '@web-shared/useChatWidth.ts';
 import { EmptyState } from '@web-shared/desk/module-kit.tsx';
+import { startFallbackPolling } from './fallback-poll.ts';
 import { queryKeys } from './query.ts';
 
 type ModuleKey = 'tasks' | 'approvals' | 'messages' | 'minutes' | 'report';
@@ -40,6 +41,9 @@ const NAV_MODULES: ReadonlyArray<{ key: ModuleKey; label: string; icon: string }
   { key: 'report', label: '汇报', icon: 'bar-chart' },
 ];
 
+/** 兜底轮询周期 —— 用户定 10 秒:比这密就成了轮询,比这疏推送漏了人等得出来 */
+const FALLBACK_POLL_MS = 10_000;
+
 export function AppShell() {
   const queryClient = useQueryClient();
   const [module, setModule] = useState<ModuleKey>('tasks');
@@ -109,6 +113,19 @@ export function AppShell() {
    */
   const detailPending = current !== '' && detail.isPending;
 
+  /*
+   * SSE 的兜底:任务界面开着的时候每 10 秒把 `desk` 下在用的查询(清单 / 这一单 / 角标)
+   * 各重取一次 —— 推送漏了画面最多旧 10 秒,不必等人按刷新(2026-08-28 用户定)。
+   * 离开这一屏(切模块 / 壳层卸载)effect 清理即 `stop()`,定时器与可见性监听一起摘。
+   */
+  useEffect(
+    () =>
+      module === 'tasks'
+        ? startFallbackPolling(queryClient, { intervalMs: FALLBACK_POLL_MS, prefix: queryKeys.desk })
+        : undefined,
+    [module, queryClient],
+  );
+
 
 
 
diff --git a/apps/web/src/app/fallback-poll.ts b/apps/web/src/app/fallback-poll.ts
new file mode 100644
index 0000000..51e7186
--- /dev/null
+++ b/apps/web/src/app/fallback-poll.ts
@@ -0,0 +1,57 @@
+/**
+ * SSE 的兜底轮询 —— **推送丢了,画面最多旧 10 秒**(2026-08-28 用户定)。
+ *
+ * 刷新的正路仍是订阅层(`subscribe.ts`:推送到了 → 按键失效 → 重取);这里只是兜底:
+ * 断线那几秒漏掉的推送、桥没接上的那一台、任何一处忘了广播的写路由 —— 从前都得靠人按刷新。
+ * 编码规范 §9.2「组件禁止自行轮询」照旧算数:兜底只此一处、由壳层起停,组件不许各自再起定时器。
+ *
+ * 三条约束:
+ *   · 只重取**在用的**查询(`type: 'active'`,挂着观察者的才算)—— 早已离开的屏留在缓存里的键不碰;
+ *   · **不取消在途请求**(`cancelRefetch: false`):慢接口正飞着,兜底那一下只是等它,不把它掐掉重发;
+ *   · 页签藏起来不打(后台页签打接口是纯浪费),回到前台先补一趟。
+ *
+ * 连接是 I/O,节奏是逻辑:`doc` 可注入,测试里拨 hidden 与 visibilitychange 就能钉死起停。
+ * 返回 `stop()` —— 离开界面必须调它,定时器与监听一起摘。
+ */
+import type { QueryClient } from '@tanstack/react-query';
+
+export type VisibilitySource = {
+  readonly hidden: boolean;
+  addEventListener(type: 'visibilitychange', handler: () => void): void;
+  removeEventListener(type: 'visibilitychange', handler: () => void): void;
+};
+
+export type FallbackPollingOptions = {
+  /** 周期(毫秒);工作台任务界面定 10 秒 */
+  readonly intervalMs: number;
+  /** 重取哪一支查询(按键前缀) */
+  readonly prefix: readonly unknown[];
+  /** 可见性来源;不传用 `document` */
+  readonly doc?: VisibilitySource;
+};
+
+export function startFallbackPolling(queryClient: QueryClient, options: FallbackPollingOptions): () => void {
+  const doc: VisibilitySource = options.doc ?? document;
+  let stopped = false;
+
+  const sweep = (): void => {
+    if (stopped || doc.hidden) return;
+    // 取不回来不算兜底的错:那一把查询自己会带着 error 状态,画面照实摆
+    // `cancelRefetch` 是第二参(RefetchOptions),写进过滤器会被无视、实际走默认 true —— 测试逮过一次
+    void queryClient
+      .refetchQueries({ queryKey: options.prefix, type: 'active' }, { cancelRefetch: false })
+      .catch(() => undefined);
+  };
+  const onVisibility = (): void => {
+    if (!doc.hidden) sweep();
+  };
+
+  const timer = setInterval(sweep, options.intervalMs);
+  doc.addEventListener('visibilitychange', onVisibility);
+
+  return () => {
+    stopped = true;
+    clearInterval(timer);
+    doc.removeEventListener('visibilitychange', onVisibility);
+  };
+}
diff --git a/apps/web/src/app/query.ts b/apps/web/src/app/query.ts
index 982d02e..e6f2a06 100644
--- a/apps/web/src/app/query.ts
+++ b/apps/web/src/app/query.ts
@@ -10,7 +10,7 @@ export { queryKeys };
 export const queryClient = new QueryClient({
   defaultOptions: {
     queries: {
-      // 缓存失效由 SSE 订阅层驱动,不靠组件轮询
+      // 缓存失效由 SSE 订阅层驱动,不靠组件轮询;推送漏了有壳层的 10 秒兜底(fallback-poll.ts),组件不另起定时器
       refetchOnWindowFocus: false,
       retry: 1,
       staleTime: 5_000,
diff --git a/apps/web/src/app/subscribe.ts b/apps/web/src/app/subscribe.ts
index fdf3bc8..42ffeeb 100644
--- a/apps/web/src/app/subscribe.ts
+++ b/apps/web/src/app/subscribe.ts
@@ -69,7 +69,7 @@ export function invalidateFor(queryClient: QueryClient, touch: Touch): void {
          * 负责人的工作台列表上;不连 `desk` 一起失效,那儿会留着一张点进去就 404 的卡片。
          */
         void queryClient.invalidateQueries({ queryKey: ['gov'] });
-        void queryClient.invalidateQueries({ queryKey: ['desk'] });
+        void queryClient.invalidateQueries({ queryKey: queryKeys.desk });
         break;
   }
 }
diff --git a/apps/web/src/shared/query-keys.ts b/apps/web/src/shared/query-keys.ts
index 1a918c1..6991627 100644
--- a/apps/web/src/shared/query-keys.ts
+++ b/apps/web/src/shared/query-keys.ts
@@ -6,6 +6,8 @@
 export const queryKeys = {
   /** 「我是谁、能进哪几个端」—— ADR-012 后身份来自 `GET /api/me`(Principal) */
   me: ['me'] as const,
+  /** 工作台整支 —— 失效 / 兜底轮询按这个前缀扫,下面四把都在它名下 */
+  desk: ['desk'] as const,
   tasks: ['desk', 'tasks'] as const,
   task: (id: string) => ['desk', 'task', id] as const,
   messages: ['desk', 'messages'] as const,
diff --git a/docs/编码规范.md b/docs/编码规范.md
index 0abaea8..48153b3 100644
--- a/docs/编码规范.md
+++ b/docs/编码规范.md
@@ -390,6 +390,7 @@ S-FEEL 子集(OS 03 定义域)的解析与求值,纯函数。被 `process`(边
 - 视图区容器渲染活动推送的 HTML:**沙箱 iframe(`srcdoc` + `sandbox` 属性)或净化后注入,二选一由 `ui-kit` 的 `ViewContainer` 统一实现,feature 不得自行 `dangerouslySetInnerHTML`**;无脚本执行权(AM 07)
 - 卡片表单由 `@contracts/card.ts` schema 驱动渲染与校验,与后端回传校验同 schema
 - SSE 事件到达 → 按信封目标(任务/工作流/要素)**失效对应 TanStack Query 缓存**,由订阅层统一做;组件禁止自行轮询或手写缓存
+- 推送的兜底**只此一处**:`app/fallback-poll.ts`,工作台任务界面开着时每 10 秒把 `desk` 下在用的查询重取一遍(不取消在途、页签藏起不打、离开即停),由壳层起停 —— 组件仍不许各自起定时器(2026-08-28)
 - 路由状态即应用状态:当前区/页签/下钻栈可从 URL 完整还原(TanStack Router 类型化 search params);内存路由栈只是原型期形态,正式系统必须可深链
 
 ---