diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts
index 5f9894c3280..bf4b2b88d56 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts
@@ -14,6 +14,7 @@ import {
 
 export class StructuredAgentSessionEventRecovery {
   private readonly sinkFailures = new Set<string>()
+  private readonly pendingSinkRecoveries = new Set<Promise<void>>()
 
   constructor(
     private readonly context: {
@@ -35,7 +36,7 @@ export class StructuredAgentSessionEventRecovery {
       return
     }
     this.sinkFailures.add(sessionId)
-    void this.context
+    const recovery = this.context
       .serialize(sessionId, async () => {
         const session = this.context.sessions.get(sessionId)
         const stop =
@@ -61,6 +62,18 @@ export class StructuredAgentSessionEventRecovery {
       .then((event) => (event ? this.handle(event) : undefined))
       .catch((recoveryError) => this.context.onBarrierError(sessionId, recoveryError))
       .finally(() => this.sinkFailures.delete(sessionId))
+      .then(() => undefined)
+    this.pendingSinkRecoveries.add(recovery)
+    void recovery.then(
+      () => this.pendingSinkRecoveries.delete(recovery),
+      () => this.pendingSinkRecoveries.delete(recovery)
+    )
+  }
+
+  async drainSinkRecoveries(): Promise<void> {
+    while (this.pendingSinkRecoveries.size > 0) {
+      await Promise.allSettled(this.pendingSinkRecoveries)
+    }
   }
 
   async handle(event: StructuredAgentSessionLifecycleEvent): Promise<void> {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
index aef76c16cdb..f2c005fd7b4 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
@@ -267,7 +267,8 @@ export class StructuredAgentSessionHost {
           run: () => withTimeout(this.handoffs.drain(), HANDOFF_DRAIN_TIMEOUT_MS, undefined)
         },
         { name: 'drain-attaches', run: () => this.tasks.drainAttaches() },
-        { name: 'flush-event-sinks', run: () => this.runtimeState.flushAllEventSinks() }
+        { name: 'flush-event-sinks', run: () => this.runtimeState.flushAllEventSinks() },
+        { name: 'drain-sink-recoveries', run: () => this.eventRecovery.drainSinkRecoveries() }
       ],
       sessions: this.sessions
     })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts
index 230e39cdaef..d6eaa92176e 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts
@@ -273,6 +273,51 @@ describe('a session evicted and opened again', () => {
 })
 
 describe('an unexpected provider exit', () => {
+  it('drains sink-failure lease persistence before closing the host', async () => {
+    await attach()
+    const session = (
+      host as unknown as {
+        sessions: Map<string, { journal: { appendItem: (...args: never[]) => Promise<unknown> } }>
+      }
+    ).sessions.get(SESSION)!
+    const settlementStarted = Promise.withResolvers<void>()
+    const settlementGate = Promise.withResolvers<void>()
+    const originalTransition = store.transitionHandoff.bind(store)
+    vi.spyOn(store, 'transitionHandoff').mockImplementationOnce(async (...args) => {
+      settlementStarted.resolve()
+      await settlementGate.promise
+      return originalTransition(...args)
+    })
+    vi.spyOn(session.journal, 'appendItem').mockRejectedValueOnce(new Error('disk unavailable'))
+    sink?.appendItem(
+      { provider: 'codex', threadId: THREAD, turnId: 'turn-1', ordinal: 1 },
+      { kind: 'message', role: 'assistant', blocks: [{ type: 'text', text: 'lost write' }] }
+    )
+    await settlementStarted.promise
+    const runtimeState = (
+      host as unknown as {
+        runtimeState: { eventSinkFor: (id: string) => unknown }
+      }
+    ).runtimeState
+    runtimeState.eventSinkFor(SESSION)
+    let drained = false
+    const teardown = host.flushAllStreamedEvents().then(() => {
+      drained = true
+    })
+    try {
+      // Probe quiescence while persistence is held, matching the handoff teardown contract.
+      for (let tick = 0; tick < 20; tick += 1) {
+        await new Promise((resolve) => setTimeout(resolve, 0))
+      }
+      expect(drained).toBe(false)
+    } finally {
+      settlementGate.resolve()
+      await teardown
+    }
+    expect(store.getRecord(SESSION)?.lease.claimStatus).toBe('released')
+    expect(host.hasSession(SESSION)).toBe(false)
+  })
+
   it('turns a journal sink failure into observed-exit settlement and lease release', async () => {
     await attach()
     const session = (