Update custom_tools.py

custom_tools.py

@@ -23,7 +23,7 @@ class WebpageStructureAnalyzerTool(Tool):
     )
     # Use Pydantic V2's .model_json_schema() to get the dict
     inputs: dict = WebpageStructureInputs.model_json_schema()
-    output_type: str
+    output_type: str = "string"
 
     def run(self, url) -> str:
         """