diff --git a/lang_agent/tool_manager.py b/lang_agent/tool_manager.py
index 83c8d14..85bbff4 100644
--- a/lang_agent/tool_manager.py
+++ b/lang_agent/tool_manager.py
@@ -125,5 +125,5 @@ class ToolManager:
 
         return self.langchain_tools
     
-    def get_list_langchain_tools(self):
+    def get_list_langchain_tools(self)->List[StructuredTool]:
         return self.langchain_tools
\ No newline at end of file