diff --git a/src/main/providers/local-pty-provider-foreground-process.test.ts b/src/main/providers/local-pty-provider-foreground-process.test.ts
index 78bb8b4ca46..c17cc4909c7 100644
--- a/src/main/providers/local-pty-provider-foreground-process.test.ts
+++ b/src/main/providers/local-pty-provider-foreground-process.test.ts
@@ -281,6 +281,43 @@ describe('LocalPtyProvider', () => {
       }
     })
 
+    it('keeps short-circuiting a live agent instead of scanning on every call', async () => {
+      // The age bound must mean "time since we last confirmed the agent", not
+      // "how long the agent has run". Stamping only on a CHANGE of name makes a
+      // steadily-recognized agent age out permanently: the short-circuit dies
+      // after 30s, every call runs the whole-table scan, and one available-but-
+      // agentless snapshot then deletes a LIVE agent -- the false "agent done"
+      // #9258 exists to prevent.
+      Object.defineProperty(process, 'platform', { configurable: true, value: 'win32' })
+      mockProc.process = 'powershell.exe'
+      resolveAgentForegroundProcessMock.mockResolvedValue({
+        available: true,
+        processName: 'claude'
+      })
+      readWindowsPtyJobProcessIdsMock.mockReturnValue(new Set([12345, 999]))
+      vi.useFakeTimers({ toFake: ['Date'] })
+      try {
+        vi.setSystemTime(1_000_000)
+        const { id } = await provider.spawn({ cols: 80, rows: 24 })
+
+        await expect(provider.getForegroundProcess(id)).resolves.toBe('claude')
+        expect(resolveAgentForegroundProcessMock).toHaveBeenCalledTimes(1)
+
+        // Past the bound: one revalidating scan is expected, and it re-confirms.
+        vi.setSystemTime(1_000_000 + 40_000)
+        await expect(provider.getForegroundProcess(id)).resolves.toBe('claude')
+        expect(resolveAgentForegroundProcessMock).toHaveBeenCalledTimes(2)
+
+        // That confirmation must restart the clock, so the short-circuit resumes.
+        vi.setSystemTime(1_000_000 + 45_000)
+        await expect(provider.getForegroundProcess(id)).resolves.toBe('claude')
+        await expect(provider.getForegroundProcess(id)).resolves.toBe('claude')
+        expect(resolveAgentForegroundProcessMock).toHaveBeenCalledTimes(2)
+      } finally {
+        vi.useRealTimers()
+      }
+    })
+
     it('falls through to the scan when the job holds only the shell', async () => {
       Object.defineProperty(process, 'platform', { configurable: true, value: 'win32' })
       mockProc.process = 'powershell.exe'
diff --git a/src/main/providers/local-pty-provider.ts b/src/main/providers/local-pty-provider.ts
index 224e028e08d..b160515b43b 100644
--- a/src/main/providers/local-pty-provider.ts
+++ b/src/main/providers/local-pty-provider.ts
@@ -1473,9 +1473,10 @@ export class LocalPtyProvider implements IPtyProvider {
         lastRecognizedAgent
       )
       if (stable.lastRecognizedAgent) {
-        if (ptyLastRecognizedForeground.get(id) !== stable.lastRecognizedAgent) {
-          ptyLastRecognizedForegroundAt.set(id, Date.now())
-        }
+        // Every confirmation restarts the clock: the bound means "time since we
+        // last saw the agent", not "how long it has run". Stamping only on a
+        // change would age out a live agent that keeps being recognized.
+        ptyLastRecognizedForegroundAt.set(id, Date.now())
         ptyLastRecognizedForeground.set(id, stable.lastRecognizedAgent)
       } else {
         ptyLastRecognizedForeground.delete(id)
diff --git a/src/main/providers/windows-cached-agent-revalidation.ts b/src/main/providers/windows-cached-agent-revalidation.ts
index 05a605ef23e..eb73b202870 100644
--- a/src/main/providers/windows-cached-agent-revalidation.ts
+++ b/src/main/providers/windows-cached-agent-revalidation.ts
@@ -5,9 +5,16 @@ import { isShellProcess } from '../../shared/shell-process-detection'
  *
  * The job is a SUPERSET of the console: it keeps console-detached descendants,
  * so "something besides the shell is alive" cannot tell a working agent from a
- * leftover. A WSL pane always has some, so treating that as proof of life pins
- * a dead agent's name forever (#9258's bug, reached by a new route). Age is the
- * tiebreak. 5x the renderer's 6s confirm ladder.
+ * leftover. Any pane that keeps one -- and whose fallback name reads as a shell
+ * -- would otherwise pin a dead agent's name forever (#9258's bug, reached by a
+ * new route). Age is the tiebreak.
+ *
+ * The invariant both callers must preserve: every successful recognition resets
+ * the clock, so this can only expire an identity no scan has confirmed for this
+ * long. It is never a timeout on a live agent.
+ *
+ * 5x the renderer's 6s confirm ladder, and bounded above by the fact that a
+ * stale cache also pins the refresh at the 1s TTL until it clears.
  */
 export const WINDOWS_DETACHED_DESCENDANT_IDENTITY_MAX_AGE_MS = 30_000