fix: prevent blank browser reloads and clear stale errors

Require a committed page URL before enabling reload. Clear sidebar action errors when leaving or closing a panel, and ignore late failures from its previous scope.

Add regression coverage and document browser error lifecycle and validation results.

Release note: 修复空白浏览器页刷新时报错、关闭浏览器后错误提示仍残留的问题；切换或关闭面板后，旧操作的延迟失败不再重新显示。

docs/features/assistant-workbar/browser-tabs-technical-design.md

@@ -89,7 +89,10 @@ Tab 的跨会话可见性与 MCP 授权分开处理。B 的请求不能选择属
 capability 在用户切到 B 后仍固定路由至 A 的原 Tab，使用租约也继续阻止关闭该 Tab。
 内部点击实例只同步应用类型，不再次按当前 Conversation 改选实例。Main 状态携带对应的
 `workbarInstanceId`，Renderer 据此绑定请求创建的同一 Tab，而不是另建空白页。收到 `stopped`
-后清除该实例的旧 Tab 绑定，下一次使用通过原逻辑实例重新创建，保留地址草稿与错误反馈。
+后清除该实例的旧 Tab 绑定，下一次使用通过原逻辑实例重新创建，保留地址草稿。
+刷新可用性读取 Main 的已提交 URL，不使用地址草稿或仅凭 `sessionActive` 判断。
+侧栏操作错误以当前工作栏实例和面板展开状态为作用域；切换或关闭时清空，旧作用域的
+异步回调不再写入错误，即使用户随后返回同一实例。
 请求创建的实例也遵守现有 32 个工作栏页签上限；满额时保留 Main 页面及其状态，并就地提示
 关闭一个可关闭页签。释放位置后再绑定该页面，不写入超限布局或丢弃 Agent 页面。
 
@@ -173,7 +176,7 @@ primary, including one opened by an Agent, is not adopted by a new instance. New
 
 持久化工作栏实例 ID、顺序、自定义标题和公开 Conversation 绑定，不持久化页面进程、CDP
 引用、snapshot、viewport lease、Cookie、Token 或 Main `BrowserTabId`。应用重启后实例显示
-未启动状态，首次导航或 Agent 使用时按原绑定创建新 Tab。
+未启动状态，展开浏览器面板或 Agent 首次使用时按原绑定创建新 Tab。
 
 绑定的 Conversation 已删除或不可见时保留实例并显示目标失效，不自动绑定当前 Conversation。
 

docs/features/assistant-workbar/prd.md

@@ -473,6 +473,10 @@ Renderer 不接收任意系统 PID 控制能力。控制动作引用 Main 签发
 页面加载期间原位切换为“停止加载”；“关闭浏览器”是清楚独立于导航的会话生命周期操作，
 必须与“停止加载”在文案和视觉上明确区分。现有“停止浏览器”语义统一改名为“关闭浏览器”。
 
+新建或重新创建的空白标签页尚无已提交 URL 时禁用刷新；只输入地址草稿不会启用刷新。
+首次导航期间仍可停止加载。操作错误仅在当前面板本次打开期间显示，切换面板、关闭当前
+页签或收起工作栏后清除，已离开面板的异步失败不得重新显示旧提示。
+
 同一 Conversation 下的 Browser Tab 共享隔离存储和代理上下文，但每个 Tab 拥有独立页面、
 导航状态、操作队列和元素引用空间。模型请求开始时绑定一个确定的 Browser Tab；用户切换
 工作栏实例不能在请求途中改变 Agent 的工具目标。用户在该实例执行前往、返回或刷新会有意

docs/features/assistant-workbar/progress.md

@@ -1,5 +1,21 @@
 # 工作栏实现与验证进度
 
+## 2026-09-12 浏览器刷新与关闭后的错误清理
+
+- 按 [浏览器工具栏规则](./prd.md#77-浏览器) 修复空白标签页允许刷新的问题；
+  刷新需要 Main 的已提交 URL，地址草稿不启用刷新，首次导航仍可停止加载。
+- 侧栏操作错误在切换面板、关闭当前页签或收起工作栏后清除；旧面板的异步失败不再回写。
+  作用域实现见 [浏览器多实例技术设计](./browser-tabs-technical-design.md#4-renderer-与-viewport)。
+- Sidebar 回归 38 项、App 浏览器筛选回归 5 项、BrowserService 回归 43 项通过。
+  `node build/run-browser-tabs-electron-e2e.cjs` 通过，验证真实空白页、导航、页面隔离和关闭；
+  该脚本不覆盖 Renderer 提示显示，提示清理由组件测试验证，本轮未手动操作完整桌面 UI。
+- `npm run typecheck` 和两份修改源码的 ESLint 检查通过。全量 `npm test` 在 Agent
+  离线依赖清单用例超时后，整轮达到 200 秒执行上限；包含完整 App 测试的补跑也达到该上限。
+  `npm run lint` 被工作区原有未跟踪的 `application-tool-navigation/navigation-demo.js`
+  中 27 项浏览器全局变量错误阻断，未修改该文件，不将整库校验记为全绿。
+- 本轮仅修改桌面 Renderer 控件与提示状态，未改 BrowserService、Runtime、Agent 或远程协议；
+  不需要单独的远程实现。无外部模型调用。
+
 ## 2026-09-10 提交后保留问答
 
 - 桌面端在提交成功后保留结构化问答回顾，支持多轮回答、跳过及本地会话重新加载；

src/renderer/src/RightAssistantSidebar.resize.test.tsx

@@ -122,6 +122,7 @@ const currentProject: AssistantProject = {
 }
 
 function sidebarElement({
+  open = true,
   tab = 'tasks',
   approvals = [],
   artifacts = [],
@@ -144,6 +145,7 @@ function sidebarElement({
   onStopLoadingBrowser,
   onTabChange = vi.fn()
 }: {
+  open?: boolean
   tab?: AssistantSidebarTab
   approvals?: PendingSidebarApproval[]
   artifacts?: SidebarArtifact[]
@@ -206,7 +208,7 @@ function sidebarElement({
         onStopLoadingBrowser={onStopLoadingBrowser}
         onOpenTask={vi.fn()}
         onTabChange={onTabChange}
-        open
+        open={open}
         restoreFocusRef={restoreFocusRef}
         tab={tab}
         workspaceProjectId={workspaceProjectId}
@@ -822,6 +824,112 @@ describe('RightAssistantSidebar resizing', () => {
     ).not.toBeInTheDocument()
   })
 
+  it('requires a committed URL to reload a fresh active browser tab, but still allows Stop', async () => {
+    const conversationId = 'blank-browser'
+    const state: BrowserLiveState = {
+      ...browserSummary(conversationId, firstBrowserTabId, true),
+      sessionActive: true
+    }
+    const onReloadBrowser = vi.fn(async () => undefined)
+    const onStopLoadingBrowser = vi.fn(async () => undefined)
+    const props = {
+      tab: 'browser' as const,
+      activeConversationId: conversationId,
+      onReloadBrowser,
+      onStopLoadingBrowser
+    }
+    const withState = (browserState: BrowserLiveState) => sidebarElement({
+      ...props, browserStates: { [conversationId]: { [firstBrowserTabId]: browserState } }
+    })
+    const view = render(withState(state))
+    await waitFor(() => expect(browserApi.createTab).toHaveBeenCalledOnce())
+    expect(screen.getByRole('button', { name: '刷新' })).toBeDisabled()
+    fireEvent.change(screen.getByRole('textbox', { name: '浏览器地址' }), {
+      target: { value: 'https://draft.example/' }
+    })
+    fireEvent.click(screen.getByRole('button', { name: '刷新' }))
+    expect(screen.getByRole('button', { name: '刷新' })).toBeDisabled()
+    expect(onReloadBrowser).not.toHaveBeenCalled()
+
+    view.rerender(withState({ ...state, status: 'loading', isLoading: true }))
+    expect(screen.getByRole('button', { name: '停止加载' })).toBeEnabled()
+    fireEvent.click(screen.getByRole('button', { name: '停止加载' }))
+    await waitFor(() => expect(onStopLoadingBrowser).toHaveBeenCalledWith(conversationId, firstBrowserTabId))
+
+    view.rerender(withState({ ...state, url: 'https://committed.example/' }))
+    expect(screen.getByRole('button', { name: '刷新' })).toBeEnabled()
+    fireEvent.click(screen.getByRole('button', { name: '刷新' }))
+    await waitFor(() => expect(onReloadBrowser).toHaveBeenCalledWith(conversationId, firstBrowserTabId))
+  })
+
+  it.each(['close', 'switch', 'collapse'] as const)(
+    'clears a browser action error after %s without restoring it on return',
+    async (transition) => {
+      const props = {
+        tab: 'browser' as const,
+        activeConversationId: 'error-browser',
+        onNavigateBrowser: vi.fn().mockRejectedValue(new Error('Navigation failed'))
+      }
+      const view = render(sidebarElement(props))
+      await waitFor(() => expect(browserApi.createTab).toHaveBeenCalledOnce())
+      fireEvent.change(screen.getByRole('textbox', { name: '浏览器地址' }), {
+        target: { value: 'https://example.com/' }
+      })
+      fireEvent.click(screen.getByRole('button', { name: '前往' }))
+      expect(await screen.findByRole('alert')).toHaveTextContent('Navigation failed')
+
+      if (transition === 'close') {
+        fireEvent.click(screen.getByRole('button', { name: '关闭浏览器 · error-browser' }))
+        await waitFor(() => expect(screen.queryByRole('tab', { name: '浏览器 · error-browser' })).not.toBeInTheDocument())
+        fireEvent.click(screen.getByRole('button', { name: '打开工作栏应用' }))
+        fireEvent.click(screen.getByText('浏览器', { selector: 'strong' }).closest('button')!)
+        await waitFor(() => expect(browserApi.createTab).toHaveBeenCalledTimes(2))
+      } else if (transition === 'switch') {
+        fireEvent.click(screen.getByRole('tab', { name: '工作区' }))
+        expect(screen.queryByText('Navigation failed')).not.toBeInTheDocument()
+        fireEvent.click(screen.getByRole('tab', { name: '浏览器 · error-browser' }))
+      } else {
+        view.rerender(sidebarElement({ ...props, open: false }))
+        view.rerender(sidebarElement(props))
+      }
+      expect(screen.queryByText('Navigation failed')).not.toBeInTheDocument()
+    }
+  )
+
+  it.each(['close', 'switch', 'collapse'] as const)(
+    'ignores a late browser action failure after %s',
+    async (transition) => {
+      let rejectNavigation!: (reason: Error) => void
+      const props = {
+        tab: 'browser' as const,
+        activeConversationId: 'late-browser',
+        onNavigateBrowser: vi.fn(() => new Promise<void>((_resolve, reject) => {
+          rejectNavigation = reject
+        }))
+      }
+      const view = render(sidebarElement(props))
+      await waitFor(() => expect(browserApi.createTab).toHaveBeenCalledOnce())
+      fireEvent.change(screen.getByRole('textbox', { name: '浏览器地址' }), {
+        target: { value: 'https://example.com/' }
+      })
+      fireEvent.click(screen.getByRole('button', { name: '前往' }))
+      await waitFor(() => expect(props.onNavigateBrowser).toHaveBeenCalledOnce())
+
+      if (transition === 'close') {
+        fireEvent.click(screen.getByRole('button', { name: '关闭浏览器 · late-browser' }))
+        await waitFor(() => expect(screen.queryByRole('tab', { name: '浏览器 · late-browser' })).not.toBeInTheDocument())
+      } else if (transition === 'switch') {
+        fireEvent.click(screen.getByRole('tab', { name: '工作区' }))
+        fireEvent.click(screen.getByRole('tab', { name: '浏览器 · late-browser' }))
+      } else {
+        view.rerender(sidebarElement({ ...props, open: false }))
+      }
+      await act(async () => rejectNavigation(new Error('Late navigation failed')))
+      if (transition === 'collapse') view.rerender(sidebarElement(props))
+      expect(screen.queryByText('Late navigation failed')).not.toBeInTheDocument()
+    }
+  )
+
   it('keeps browser A selected and usable after switching to B, and binds a new browser to B', async () => {
     const onNavigateBrowser = vi.fn(async () => undefined)
     const onBackBrowser = vi.fn(async () => undefined)
@@ -1204,8 +1312,36 @@ describe('RightAssistantSidebar resizing', () => {
     expect(
       screen.getByRole('tab', { name: '浏览器 · conversation-a' })
     ).toBeInTheDocument()
+
+    fireEvent.click(screen.getByRole('button', { name: '关闭浏览器 · conversation-a' }))
+    await waitFor(() => expect(screen.queryByRole('tab', { name: '浏览器 · conversation-a' })).not.toBeInTheDocument())
+    expect(screen.queryByText('Close denied')).not.toBeInTheDocument()
   })
 
+  it.each(['create', 'close'] as const)(
+    'ignores a late browser %s failure after switching panels',
+    async (operation) => {
+      let rejectOperation!: (reason: Error) => void
+      const pending = new Promise<never>((_resolve, reject) => {
+        rejectOperation = reject
+      })
+      if (operation === 'create') browserApi.createTab.mockReturnValueOnce(pending)
+      else browserApi.closeTab.mockReturnValueOnce(pending)
+      renderSidebar({ tab: 'browser', activeConversationId: 'late-browser' })
+      await waitFor(() => expect(browserApi.createTab).toHaveBeenCalledOnce())
+      if (operation === 'close') {
+        fireEvent.click(screen.getByRole('button', { name: '关闭浏览器 · late-browser' }))
+        await waitFor(() => expect(browserApi.closeTab).toHaveBeenCalledOnce())
+      }
+      fireEvent.click(screen.getByRole('tab', { name: '工作区' }))
+      await act(async () => rejectOperation(new Error('Late browser failure')))
+      expect(screen.queryByText('Late browser failure')).not.toBeInTheDocument()
+      fireEvent.click(screen.getByRole('tab', { name: '浏览器 · late-browser' }))
+      await waitFor(() => expect(browserApi.createTab).toHaveBeenCalledTimes(operation === 'create' ? 2 : 1))
+      expect(screen.queryByText('Late browser failure')).not.toBeInTheDocument()
+    }
+  )
+
   it('rebinds a released tab before retrying navigation and can close a released instance', async () => {
     const conversationId = 'retry-browser'
     const onNavigateBrowser = vi.fn(async () => undefined)

src/renderer/src/RightAssistantSidebar.tsx

@@ -321,6 +321,7 @@ function BrowserToolbar({
   const refreshDisabled =
     operationBlocked ||
     !sessionActive ||
+    !authoritativeUrl ||
     isLoading
   const goDisabled =
     actionPending ||
@@ -803,7 +804,23 @@ export function RightAssistantSidebar({
   const [taskScope, setTaskScope] = useState<WorkbarTaskScope>(
     initialLayout?.taskScope ?? 'current-project'
   )
-  const [actionError, setActionError] = useState('')
+  const [actionErrorState, setActionErrorState] = useState({
+    scope: { instanceId: activeWorkbarInstanceId, open },
+    message: ''
+  })
+  const actionErrorScope = actionErrorState.scope
+  const actionError = actionErrorState.message
+  if (actionErrorScope.instanceId !== activeWorkbarInstanceId || actionErrorScope.open !== open) {
+    setActionErrorState({ scope: { instanceId: activeWorkbarInstanceId, open }, message: '' })
+  }
+  const setActionError = useCallback((message: string): void => {
+    // Old callbacks cannot restore an error after leaving and returning to a panel.
+    setActionErrorState((current) =>
+      current.scope === actionErrorScope && actionErrorScope.open
+        ? { ...current, message }
+        : current
+    )
+  }, [actionErrorScope])
   const [terminalSessionIds, setTerminalSessionIds] = useState<
     Record<string, string>
   >({})
@@ -1271,7 +1288,7 @@ export function RightAssistantSidebar({
             tabId = binding?.tabId
             conversationId = binding?.conversationId
           } catch (reason) {
-            setActionError(
+            if (instance.id === activeWorkbarInstanceId) setActionError(
               reason instanceof Error
                 ? reason.message
                 : t('sidebar.errors.closeBrowser')
@@ -1283,7 +1300,7 @@ export function RightAssistantSidebar({
           try {
             await window.goodbuddy.browser.closeTab?.({ conversationId, tabId })
           } catch (reason) {
-            setActionError(
+            if (instance.id === activeWorkbarInstanceId) setActionError(
               reason instanceof Error
                 ? reason.message
                 : t('sidebar.errors.closeBrowser')
@@ -1326,6 +1343,8 @@ export function RightAssistantSidebar({
       return true
     },
     [
+      activeWorkbarInstanceId,
+      setActionError,
       removeWorkbarInstance,
       localizedAppDefinitions,
       terminalAdapter,
@@ -1654,7 +1673,7 @@ export function RightAssistantSidebar({
           : t('sidebar.errors.browserControlUnavailable')
       )
     })
-  }, [activeWorkbarInstance, ensureBrowserTab, hasUnboundRequestBrowser, open, t])
+  }, [activeWorkbarInstance, ensureBrowserTab, hasUnboundRequestBrowser, open, setActionError, t])
 
   return (
     <aside