diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.test.ts
index 02e73e8e73b..e08c289c87a 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.test.ts
@@ -187,7 +187,7 @@ describe('StructuredAgentSessionAdapterRouter.closeAll', () => {
     expect(acquire).not.toHaveBeenCalled()
   })
 
-  it('publishes one global close proof without retaining session ids', async () => {
+  it('keeps a per-session stop proof and reports no stop for a session it never routed', async () => {
     const claude = adapterOf(vi.fn(async () => true))
     const closeAdapters = vi.fn(async () => undefined)
     const router = new StructuredAgentSessionAdapterRouter(
@@ -202,14 +202,30 @@ describe('StructuredAgentSessionAdapterRouter.closeAll', () => {
 
     await router.closeAll()
 
+    // The routed session carries the shutdown's own exit proof; the other two are sessions this
+    // router has no record of, and an absent record is not a stop it can report.
     await expect(router.closeSession('session-1')).resolves.toBe(true)
-    await expect(router.closeSession('never-routed')).resolves.toBe(true)
+    await expect(router.closeSession('never-routed')).resolves.toBe(false)
     router.acknowledgeSessionRelease('session-1')
-    await expect(router.closeSession('session-1')).resolves.toBe(true)
+    await expect(router.closeSession('session-1')).resolves.toBe(false)
     await router.closeAll()
     expect(closeAdapters).toHaveBeenCalledOnce()
   })
 
+  it('asks the adapters to release an unrouted session rather than answering from the close proof', async () => {
+    const claudeRelease = vi.fn(async () => true)
+    const codexRelease = vi.fn(async () => false)
+    const router = new StructuredAgentSessionAdapterRouter(
+      { claude: adapterOf(claudeRelease), codex: adapterOf(codexRelease) },
+      async () => undefined
+    )
+    await router.closeAll()
+
+    await expect(router.releaseAcquisition({ sessionId: 'never-routed' })).resolves.toBe(true)
+    expect(claudeRelease).toHaveBeenCalledWith({ sessionId: 'never-routed' })
+    expect(codexRelease).toHaveBeenCalledWith({ sessionId: 'never-routed' })
+  })
+
   it('retains live routes and publishes no global proof when closeAll fails', async () => {
     const failure = new Error('adapter shutdown failed')
     const claude = adapterOf(vi.fn(async () => true))
@@ -268,9 +284,10 @@ describe('StructuredAgentSessionAdapterRouter.closeAll', () => {
     await router.closeAll()
     resolveAcquire(acquisition(2, 'spawn-2'))
 
-    // The route is NOT published behind a closed adapter, so nothing routes back out to it.
+    // The route is NOT published behind a closed adapter, so nothing routes back out to it — and
+    // with no route the router has nothing to stop and no stop to report.
     await expect(acquiring).rejects.toThrow('router is closed')
-    await expect(router.closeSession('session-1')).resolves.toBe(true)
+    await expect(router.closeSession('session-1')).resolves.toBe(false)
     expect(closeSession).not.toHaveBeenCalled()
   })
 })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.ts
index 041d9adc11e..1cc571d39aa 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-adapter-router.ts
@@ -51,9 +51,6 @@ export class StructuredAgentSessionAdapterRouter implements StructuredAgentSessi
         this.routes.delete(input.sessionId)
       }
     }
-    if (this.allAdaptersClosed) {
-      return true
-    }
     let released = false
     for (const candidate of Object.values(this.adapters)) {
       released = (await candidate.releaseAcquisition?.(input)) === true || released
@@ -145,7 +142,10 @@ export class StructuredAgentSessionAdapterRouter implements StructuredAgentSessi
   ): Promise<boolean> {
     const route = this.routes.get(sessionId)
     if (!route) {
-      return this.allAdaptersClosed
+      // No route is loss of contact, never proof of a stop. Answering `true` here would hand a
+      // caller a receipt for a session this router never acted on — and the caller spends that
+      // receipt by releasing the durable lease.
+      return false
     }
     if (route.state === 'stopped') {
       return true
@@ -169,7 +169,13 @@ export class StructuredAgentSessionAdapterRouter implements StructuredAgentSessi
     this.closePromise = (async () => {
       try {
         await this.closeAdapters()
-        this.routes.clear()
+        // Adapter shutdown only resolves once every child is PROVEN stopped, so each routed
+        // session inherits that proof and keeps it per session. Clearing the map instead would
+        // leave one boolean as the only surviving evidence, and an empty map cannot tell a
+        // session this router stopped from one it never saw.
+        for (const route of this.routes.values()) {
+          route.state = 'stopped'
+        }
         this.allAdaptersClosed = true
       } finally {
         this.closePromise = null