Update app.py

app.py

@@ -199,7 +199,7 @@ async def generate_streaming_response(messages: List[Dict], use_search: bool, te
         
         if use_search:
             llm_kwargs["tools"] = available_tools
-            llm_kwargs["tool_choice"] = "auto"
+            llm_kwargs["tool_choice"] = "required"
         
         source_links = []
         response_content = ""