diff --git a/src/agent/async-agent.ts b/src/agent/async-agent.ts
index 4fdfb616..ebc06317 100644
--- a/src/agent/async-agent.ts
+++ b/src/agent/async-agent.ts
@@ -42,6 +42,9 @@ export class AsyncAgent {
       .then(async () => {
         if (this._closed) return;
         const result = await this.agent.run(content);
+        // Flush pending session writes so waitForIdle() callers
+        // can safely read session data from disk.
+        await this.agent.flushSession();
         // Normal text is delivered via message_end event; only handle errors here
         if (result.error) {
           this.channel.send({ id: uuidv7(), content: `[error] ${result.error}` });
diff --git a/src/agent/runner.ts b/src/agent/runner.ts
index 98f233d9..00c0e3b2 100644
--- a/src/agent/runner.ts
+++ b/src/agent/runner.ts
@@ -455,6 +455,13 @@ export class Agent {
     }
   }
 
+  /**
+   * Wait for all pending session storage writes to complete.
+   */
+  async flushSession(): Promise<void> {
+    await this.session.flush();
+  }
+
   /**
    * Reload tools from profile config.
    * Call this after updating tool status to apply changes
diff --git a/src/agent/session/session-manager.ts b/src/agent/session/session-manager.ts
index ec1c7cd6..9ff19614 100644
--- a/src/agent/session/session-manager.ts
+++ b/src/agent/session/session-manager.ts
@@ -272,6 +272,13 @@ export class SessionManager {
     return result;
   }
 
+  /**
+   * Wait for all pending storage writes to complete.
+   */
+  async flush(): Promise<void> {
+    await this.queue;
+  }
+
   private enqueue(task: () => Promise<void>) {
     this.queue = this.queue.then(task, task).catch(() => {
       // Swallow storage errors to prevent unhandled rejections.