fix: wait for background shutdown notifications

.changeset/persist-runtime-model-defaults.md

@@ -3,4 +3,4 @@
 "@moonshot-ai/kimi-code": patch
 ---
 
-Persist model selections from the terminal UI to the default configuration, and honor the configured default thinking state for new sessions.
+Persist model selections from the terminal UI to the default configuration, honor the configured default thinking state for new sessions, and wait for background task terminal notifications during session shutdown before flushing records.

packages/agent-core/src/agent/background/index.ts

@@ -35,6 +35,7 @@ const NOTIFICATION_TAIL_BYTES = 3_000;
 export class BackgroundManager extends BackgroundProcessManager {
   private readonly scheduledNotificationKeys = new Set<string>();
   private readonly deliveredNotificationKeys = new Set<string>();
+  private readonly terminalNotificationPromises = new Set<Promise<void>>();
 
   constructor(
     public readonly agent: Agent,
@@ -85,7 +86,18 @@ export class BackgroundManager extends BackgroundProcessManager {
   }
 
   protected override onLiveTaskTerminal(info: BackgroundTaskInfo): void | Promise<void> {
-    return this.notifyBackgroundTask(info);
+    const promise = this.notifyBackgroundTask(info).catch(() => {});
+    this.terminalNotificationPromises.add(promise);
+    void promise.finally(() => {
+      this.terminalNotificationPromises.delete(promise);
+    });
+    return promise;
+  }
+
+  async settleTerminalNotifications(): Promise<void> {
+    while (this.terminalNotificationPromises.size > 0) {
+      await Promise.all(Array.from(this.terminalNotificationPromises));
+    }
   }
 
   private async restoreBackgroundTaskNotifications(): Promise<void> {
@@ -183,6 +195,7 @@ export class BackgroundManager extends BackgroundProcessManager {
     super._reset();
     this.scheduledNotificationKeys.clear();
     this.deliveredNotificationKeys.clear();
+    this.terminalNotificationPromises.clear();
   }
 }
 

packages/agent-core/src/session/index.ts

@@ -194,9 +194,10 @@ export class Session {
     });
     if (keepAliveOnExit) return;
     await Promise.all(
-      Array.from(this.agents.values(), (agent) =>
-        agent.background.stopAll('Session closed'),
-      ),
+      Array.from(this.agents.values(), async (agent) => {
+        await agent.background.stopAll('Session closed');
+        await agent.background.settleTerminalNotifications();
+      }),
     );
   }