diff --git a/gns3server/agent/gns3_copilot/agent_service.py b/gns3server/agent/gns3_copilot/agent_service.py
index efb4afcdf..b4e739a4b 100644
--- a/gns3server/agent/gns3_copilot/agent_service.py
+++ b/gns3server/agent/gns3_copilot/agent_service.py
@@ -11,7 +11,7 @@ import json
 import logging
 import os
 from datetime import datetime
-from typing import AsyncGenerator, Dict, Any, Optional
+from typing import AsyncGenerator, Dict, Any, Optional, List
 from uuid import uuid4
 
 import aiosqlite
@@ -177,6 +177,10 @@ class AgentService:
             mode,
         )
 
+        # Ensure checkpointer is initialized
+        if not self._checkpointer_conn:
+            await self._get_checkpointer()
+
         # Get or create chat session
         repo = ChatSessionsRepository(self._checkpointer_conn)
         session = await repo.get_session_by_thread(session_id)