diff --git a/src/routers/deep_agent_chat.py b/src/routers/deep_agent_chat.py
index e2465cb..a055cec 100644
--- a/src/routers/deep_agent_chat.py
+++ b/src/routers/deep_agent_chat.py
@@ -373,7 +373,9 @@ async def get_chat_history(thread_id: str):
     """
     config = {"configurable": {"thread_id": thread_id}, }
     history_data = []
-    main_agent = build_main_agent(False)
+
+    workspace_dir = os.path.join(PROJECT_ROOT, f"agent_workspace/{thread_id}")
+    main_agent = build_main_agent(False, workspace_dir, enable_thinking=False)
     async for state in main_agent.aget_state_history(config):
         msg_content = "Initial"
         if state.values and "messages" in state.values:
diff --git a/src/schemas/deep_agent_chat.py b/src/schemas/deep_agent_chat.py
index 19c4892..8525fe6 100644
--- a/src/schemas/deep_agent_chat.py
+++ b/src/schemas/deep_agent_chat.py
@@ -23,7 +23,7 @@ class DeepAgentChatRequest(BaseModel):
 
 class HistoryItem(BaseModel):
     checkpoint_id: str
-    last_message: str
+    last_message: Any
     node: Optional[str]
     timestamp: Any