diff --git a/src/main/agent-hooks/server.ts b/src/main/agent-hooks/server.ts
index f8c1d754fbf..013b90d7143 100644
--- a/src/main/agent-hooks/server.ts
+++ b/src/main/agent-hooks/server.ts
@@ -415,7 +415,10 @@ function equivalentParsedAgentStatusPayload(
     a.toolInput === b.toolInput &&
     a.interactivePrompt === b.interactivePrompt &&
     a.lastAssistantMessage === b.lastAssistantMessage &&
-    a.interrupted === b.interrupted
+    a.interrupted === b.interrupted &&
+    // Why: a session-boundary done must never be deduped against a cached real done —
+    // the flag has to reach receivers deterministically (STA-3386).
+    a.sessionBoundary === b.sessionBoundary
   )
 }
 
diff --git a/src/renderer/src/components/star-nag/StarNagAgentValueMomentObserver.tsx b/src/renderer/src/components/star-nag/StarNagAgentValueMomentObserver.tsx
index 1fd3099323d..42f6145b1f3 100644
--- a/src/renderer/src/components/star-nag/StarNagAgentValueMomentObserver.tsx
+++ b/src/renderer/src/components/star-nag/StarNagAgentValueMomentObserver.tsx
@@ -33,6 +33,9 @@ function hasSuccessfulDoneTransition(
       previousEntry &&
       previousEntry.state !== 'done' &&
       entry.state === 'done' &&
+      // Why: a session-boundary done is an idle connect (STA-3386), not a value moment —
+      // a stale working row + resume would otherwise nag on launch.
+      entry.sessionBoundary !== true &&
       !entry.interrupted &&
       hasMeaningfulPrompt(entry)
     ) {
diff --git a/src/renderer/src/store/slices/agent-status.test.ts b/src/renderer/src/store/slices/agent-status.test.ts
index b6b2976e26b..6965ca8bbb2 100644
--- a/src/renderer/src/store/slices/agent-status.test.ts
+++ b/src/renderer/src/store/slices/agent-status.test.ts
@@ -1399,3 +1399,103 @@ describe('agent status retention + prefix sweep', () => {
     expect(retained['tab-b:0']).toBeUndefined()
   })
 })
+
+describe('session-boundary done semantics (STA-3386)', () => {
+  const PANE = 'tab-1:11111111-1111-4111-8111-111111111111'
+
+  it('keeps the launch config registry entry alive across a session-boundary done', () => {
+    const store = createTestStore()
+    store.setState({
+      agentLaunchConfigByPaneKey: {
+        [PANE]: {
+          launchConfig: { agentArgs: '', agentEnv: {} },
+          identity: { agentType: 'claude' },
+          launchToken: 'token-1'
+        }
+      }
+    } as unknown as Partial<AppState>)
+
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: '',
+      agentType: 'claude',
+      sessionBoundary: true
+    })
+    // Why: the session just CONNECTED — the registered-launch-agent identity must survive
+    // or an idle resumed TUI loses its pane identity evidence at startup.
+    expect(store.getState().agentLaunchConfigByPaneKey[PANE]).toBeDefined()
+
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: 'fix bug',
+      agentType: 'claude',
+      lastAssistantMessage: 'Done.'
+    })
+    expect(store.getState().agentLaunchConfigByPaneKey[PANE]).toBeUndefined()
+  })
+
+  it('pushes a real completion into history when a session boundary lands on it', () => {
+    const store = createTestStore()
+    store
+      .getState()
+      .setAgentStatus(PANE, { state: 'working', prompt: 'fix bug', agentType: 'claude' })
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: 'fix bug',
+      agentType: 'claude',
+      lastAssistantMessage: 'Done.'
+    })
+
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: '',
+      agentType: 'claude',
+      sessionBoundary: true
+    })
+
+    const entry = store.getState().agentStatusByPaneKey[PANE]
+    expect(entry.sessionBoundary).toBe(true)
+    // Why: the finished timestamp and unread badge fall through to history for boundary
+    // entries — losing the real done here erases an unacknowledged completion.
+    expect(entry.stateHistory.some((h) => h.state === 'done')).toBe(true)
+  })
+
+  it('never records a session boundary itself in state history', () => {
+    const store = createTestStore()
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: '',
+      agentType: 'claude',
+      sessionBoundary: true
+    })
+    store
+      .getState()
+      .setAgentStatus(PANE, { state: 'working', prompt: 'fix bug', agentType: 'claude' })
+
+    const entry = store.getState().agentStatusByPaneKey[PANE]
+    expect(entry.stateHistory.some((h) => h.state === 'done')).toBe(false)
+  })
+
+  it('carries the flag across metadata-less done repaints but yields to turn evidence', () => {
+    const store = createTestStore()
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: '',
+      agentType: 'claude',
+      sessionBoundary: true
+    })
+
+    // Why: OSC 9999 repaints and reconnect replays re-deliver a metadata-less done.
+    store.getState().setAgentStatus(PANE, { state: 'done', prompt: '', agentType: 'claude' })
+    expect(store.getState().agentStatusByPaneKey[PANE].sessionBoundary).toBe(true)
+
+    // Why: an assistant message proves a REAL completion — the flag must not suppress it.
+    store.getState().setAgentStatus(PANE, {
+      state: 'done',
+      prompt: '',
+      agentType: 'claude',
+      lastAssistantMessage: 'Done.'
+    })
+    expect(store.getState().agentStatusByPaneKey[PANE].sessionBoundary).toBeUndefined()
+  })
+})
diff --git a/src/renderer/src/store/slices/agent-status.ts b/src/renderer/src/store/slices/agent-status.ts
index 972d569b230..95c8726f52a 100644
--- a/src/renderer/src/store/slices/agent-status.ts
+++ b/src/renderer/src/store/slices/agent-status.ts
@@ -1740,11 +1740,19 @@ export const createAgentStatusSlice: StateCreator<AppState, [], [], AgentStatusS
         // Rolling log of state transitions for the dashboard's activity blocks; push only on
         // real state changes to avoid dupes from prompt-only pings within the same state.
         // A session-boundary 'done' (idle connect, STA-3386) is not a turn event — keep it
-        // out of history so activity feeds and unread counts never surface it.
+        // out of history so activity feeds and unread counts never surface it. The inverse
+        // also holds: a boundary landing on a REAL done (resume//clear right after a finish)
+        // must push that completion into history, or the finished timestamp and unread badge
+        // lose the turn the moment the flag overwrites the live entry.
         let history: AgentStateHistoryEntry[] = existing?.stateHistory ?? []
+        const boundaryLandsOnRealDone =
+          existing?.state === 'done' &&
+          existing.sessionBoundary !== true &&
+          payload.state === 'done' &&
+          payload.sessionBoundary === true
         if (
           existing &&
-          existing.state !== payload.state &&
+          (existing.state !== payload.state || boundaryLandsOnRealDone) &&
           !(existing.state === 'done' && existing.sessionBoundary === true)
         ) {
           history = [
@@ -1939,10 +1947,15 @@ export const createAgentStatusSlice: StateCreator<AppState, [], [], AgentStatusS
           interrupted: payload.interrupted,
           // Why: done→done repaints (OSC 9999, reconnect snapshot replays) re-deliver a
           // metadata-less `done`; preserving the flag there keeps completion-reactive
-          // consumers from treating the still-idle session as newly finished.
+          // consumers from treating the still-idle session as newly finished. Turn evidence
+          // (an assistant message or a changed prompt) proves a REAL completion — never
+          // carry the flag over one, or a genuine finish could be silently suppressed.
           sessionBoundary:
             payload.sessionBoundary ??
-            (existing?.state === 'done' && payload.state === 'done'
+            (existing?.state === 'done' &&
+            payload.state === 'done' &&
+            payload.lastAssistantMessage === undefined &&
+            payload.prompt === existing.prompt
               ? existing.sessionBoundary
               : undefined)
         }
@@ -2054,8 +2067,10 @@ export const createAgentStatusSlice: StateCreator<AppState, [], [], AgentStatusS
           }
         }
         // Why: launch tokens can outlive an Orca-started TUI in the shell; once the session is done they must no longer authorize config reuse.
+        // A session-boundary done is the session CONNECTING (STA-3386) — deleting here would strip
+        // the pane's registered-launch-agent identity evidence the moment a resumed TUI sits idle.
         if (
-          (providerSessionChanged || entry.state === 'done') &&
+          (providerSessionChanged || (entry.state === 'done' && entry.sessionBoundary !== true)) &&
           paneKey in s.agentLaunchConfigByPaneKey
         ) {
           nextLaunchConfigs = { ...s.agentLaunchConfigByPaneKey }