diff --git a/backend/service/workflow_rewrite_tools.py b/backend/service/workflow_rewrite_tools.py
index 574f7ea..434b093 100644
--- a/backend/service/workflow_rewrite_tools.py
+++ b/backend/service/workflow_rewrite_tools.py
@@ -2,7 +2,7 @@
 
 import json
 import time
-from typing import Dict, Any, Optional, List
+from typing import Dict, Any, Optional, List, Union
 
 from agents.agent import Agent
 from agents.tool import function_tool
@@ -99,7 +99,7 @@ def save_checkpoint_before_modification(session_id: str, action_description: str
         return None
 
 @function_tool(strict_mode=False)
-def update_workflow(session_id: str, workflow_data: Dict[str, Any]) -> str:
+def update_workflow(session_id: str, workflow_data: Union[Dict[str, Any], str]) -> str:
     """更新当前session的工作流数据"""
     try:
         # 在修改前保存checkpoint
diff --git a/backend/utils/globals.py b/backend/utils/globals.py
index ad9e417..ba9749c 100644
--- a/backend/utils/globals.py
+++ b/backend/utils/globals.py
@@ -98,6 +98,6 @@ def set_session_id(session_id: str) -> None:
     """Set the session id."""
     _global_state.set('session_id', session_id)
 
-LLM_DEFAULT_BASE_URL = "https://comfyui-copilot-server-pre.onrender.com/v1"
-# LLM_DEFAULT_BASE_URL = "http://127.0.0.1:8000/v1"
+# LLM_DEFAULT_BASE_URL = "https://comfyui-copilot-server-pre.onrender.com/v1"
+LLM_DEFAULT_BASE_URL = "http://127.0.0.1:8000/v1"
 CLAUDE_4_MODEL_NAME = "us.anthropic.claude-sonnet-4-20250514-v1:0"