diff --git a/src/renderer/src/hooks/useAutoAckViewedAgent.focus-group.test.ts b/src/renderer/src/hooks/useAutoAckViewedAgent.focus-group.test.ts
new file mode 100644
index 00000000000..b6891321a17
--- /dev/null
+++ b/src/renderer/src/hooks/useAutoAckViewedAgent.focus-group.test.ts
@@ -0,0 +1,95 @@
+// @vitest-environment happy-dom
+
+import { act, cleanup, renderHook } from '@testing-library/react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import type * as AgentAutoAckPresence from './agent-auto-ack-presence'
+import { useAutoAckViewedAgent } from './useAutoAckViewedAgent'
+import { useAppStore } from '../store'
+import { makeTab, makeTabGroup, makeUnifiedTab } from '../store/slices/store-test-helpers'
+import { structuredAgentSessionPaneKey } from '../../../shared/structured-agent-session-projection'
+
+vi.mock('./agent-auto-ack-presence', async (importOriginal) => ({
+  ...(await importOriginal<typeof AgentAutoAckPresence>()),
+  createAutoAckPresenceCheck: (_read: unknown, onPresent: () => void) => ({
+    request: onPresent,
+    dispose() {}
+  })
+}))
+
+const WORKSPACE = 'focus-group-workspace'
+const TERMINAL_GROUP = 'terminal-group'
+const CHAT_GROUP = 'chat-group'
+const TERMINAL_TAB = 'terminal-tab'
+const CHAT_TAB = 'chat-tab'
+const CHAT_SESSION = 'chat-session'
+const CHAT_SUBJECT = structuredAgentSessionPaneKey(CHAT_TAB, CHAT_SESSION)
+
+describe('useAutoAckViewedAgent focus-group transitions', () => {
+  beforeEach(() => {
+    vi.spyOn(document, 'hasFocus').mockReturnValue(true)
+    useAppStore.setState({
+      activeView: 'terminal',
+      activeWorktreeId: WORKSPACE,
+      activeTabId: TERMINAL_TAB,
+      activeTabIdByWorktree: { [WORKSPACE]: TERMINAL_TAB },
+      activeGroupIdByWorktree: { [WORKSPACE]: TERMINAL_GROUP },
+      activeTabType: 'terminal',
+      tabsByWorktree: { [WORKSPACE]: [makeTab({ id: TERMINAL_TAB, worktreeId: WORKSPACE })] },
+      unifiedTabsByWorktree: {
+        [WORKSPACE]: [
+          makeUnifiedTab({
+            id: TERMINAL_TAB,
+            worktreeId: WORKSPACE,
+            groupId: TERMINAL_GROUP
+          }),
+          makeUnifiedTab({
+            id: CHAT_TAB,
+            worktreeId: WORKSPACE,
+            groupId: CHAT_GROUP,
+            contentType: 'agent-session',
+            entityId: CHAT_SESSION,
+            agentSessionAgent: 'claude'
+          })
+        ]
+      },
+      groupsByWorktree: {
+        [WORKSPACE]: [
+          makeTabGroup({
+            id: TERMINAL_GROUP,
+            worktreeId: WORKSPACE,
+            activeTabId: TERMINAL_TAB,
+            tabOrder: [TERMINAL_TAB]
+          }),
+          makeTabGroup({
+            id: CHAT_GROUP,
+            worktreeId: WORKSPACE,
+            activeTabId: CHAT_TAB,
+            tabOrder: [CHAT_TAB]
+          })
+        ]
+      },
+      unreadAgentCompletionPanes: { [CHAT_SUBJECT]: 'agent-completion' },
+      unreadTerminalTabs: {},
+      agentStatusByPaneKey: {},
+      retainedAgentsByPaneKey: {},
+      acknowledgedAgentsByPaneKey: {}
+    })
+  })
+
+  afterEach(() => {
+    cleanup()
+    vi.restoreAllMocks()
+  })
+
+  it('rescans when focusing a group whose structured tab becomes visible', () => {
+    renderHook(() => useAutoAckViewedAgent(false))
+    expect(useAppStore.getState().unreadAgentCompletionPanes[CHAT_SUBJECT]).toBe('agent-completion')
+
+    act(() => {
+      useAppStore.getState().focusGroup(WORKSPACE, CHAT_GROUP)
+    })
+
+    expect(useAppStore.getState().activeGroupIdByWorktree[WORKSPACE]).toBe(CHAT_GROUP)
+    expect(useAppStore.getState().unreadAgentCompletionPanes[CHAT_SUBJECT]).toBeUndefined()
+  })
+})
diff --git a/src/renderer/src/hooks/useAutoAckViewedAgent.ts b/src/renderer/src/hooks/useAutoAckViewedAgent.ts
index d2b090dc9ff..0e38b0c96c2 100644
--- a/src/renderer/src/hooks/useAutoAckViewedAgent.ts
+++ b/src/renderer/src/hooks/useAutoAckViewedAgent.ts
@@ -32,14 +32,16 @@ export function useAutoAckViewedAgent(floatingPanelVisible: boolean): void {
     // Init to undefined so the first maybeAck() (on mount) always passes the ref guard and scans.
     let lastActiveView: unknown = undefined
     let lastActiveTabId: unknown = undefined
+    let lastActiveWorktreeId: unknown = undefined
+    let lastActiveWorkspaceGroupId: unknown = undefined
+    let lastActiveWorkspaceGroups: unknown = undefined
     let lastFloatingWorkspaceActiveTabId: unknown = undefined
+    let lastFloatingWorkspaceGroupId: unknown = undefined
+    let lastFloatingWorkspaceGroups: unknown = undefined
     let lastAgentStatus: unknown = undefined
     let lastRetained: unknown = undefined
     let lastAcknowledged: unknown = undefined
     let lastLayouts: unknown = undefined
-    // Why: activating a structured chat only moves its layout group's activeTabId — no terminal
-    // slice changes, so without this the scan that clears its attention would be skipped.
-    let lastGroups: unknown = undefined
     let lastUnreadAgentCompletionPanes: unknown = undefined
 
     // `force` re-scans after a signal the store never sees: panel open/closed is React-local state.
@@ -49,18 +51,32 @@ export function useAutoAckViewedAgent(floatingPanelVisible: boolean): void {
     )
     const maybeAck = (options?: { force?: boolean; presenceConfirmed?: boolean }): void => {
       const s = useAppStore.getState()
+      const activeWorktreeId = s.activeWorktreeId
+      const activeWorkspaceGroupId = activeWorktreeId
+        ? (s.activeGroupIdByWorktree[activeWorktreeId] ?? null)
+        : null
+      const activeWorkspaceGroups = activeWorktreeId
+        ? s.groupsByWorktree[activeWorktreeId]
+        : undefined
       const floatingWorkspaceActiveTabId =
         s.activeTabIdByWorktree[FLOATING_TERMINAL_WORKTREE_ID] ?? null
+      const floatingWorkspaceGroupId =
+        s.activeGroupIdByWorktree[FLOATING_TERMINAL_WORKTREE_ID] ?? null
+      const floatingWorkspaceGroups = s.groupsByWorktree[FLOATING_TERMINAL_WORKTREE_ID]
       if (
         !options?.force &&
         s.activeView === lastActiveView &&
         s.activeTabId === lastActiveTabId &&
+        activeWorktreeId === lastActiveWorktreeId &&
+        activeWorkspaceGroupId === lastActiveWorkspaceGroupId &&
+        activeWorkspaceGroups === lastActiveWorkspaceGroups &&
         floatingWorkspaceActiveTabId === lastFloatingWorkspaceActiveTabId &&
+        floatingWorkspaceGroupId === lastFloatingWorkspaceGroupId &&
+        floatingWorkspaceGroups === lastFloatingWorkspaceGroups &&
         s.agentStatusByPaneKey === lastAgentStatus &&
         s.retainedAgentsByPaneKey === lastRetained &&
         s.acknowledgedAgentsByPaneKey === lastAcknowledged &&
         s.terminalLayoutsByTabId === lastLayouts &&
-        s.groupsByWorktree === lastGroups &&
         s.unreadAgentCompletionPanes === lastUnreadAgentCompletionPanes
       ) {
         return
@@ -69,12 +85,16 @@ export function useAutoAckViewedAgent(floatingPanelVisible: boolean): void {
       // Presence signals force a rescan; unrelated writes must not retry an away result.
       lastActiveView = s.activeView
       lastActiveTabId = s.activeTabId
+      lastActiveWorktreeId = activeWorktreeId
+      lastActiveWorkspaceGroupId = activeWorkspaceGroupId
+      lastActiveWorkspaceGroups = activeWorkspaceGroups
       lastFloatingWorkspaceActiveTabId = floatingWorkspaceActiveTabId
+      lastFloatingWorkspaceGroupId = floatingWorkspaceGroupId
+      lastFloatingWorkspaceGroups = floatingWorkspaceGroups
       lastAgentStatus = s.agentStatusByPaneKey
       lastRetained = s.retainedAgentsByPaneKey
       lastAcknowledged = s.acknowledgedAgentsByPaneKey
       lastLayouts = s.terminalLayoutsByTabId
-      lastGroups = s.groupsByWorktree
       lastUnreadAgentCompletionPanes = s.unreadAgentCompletionPanes
 
       // Why: tab-active only proxies "seen"; gate on window visible+focused so away-time transitions don't silently clear the bold signal.