fix conditional check for tool_calls in llm.py

libs/superagent/app/agents/llm.py

@@ -261,7 +261,10 @@ async def _process_stream_response(self, res: CustomStreamWrapper):
 
         async for chunk in res:
             new_message = chunk.choices[0].delta
-            if new_message.tool_calls:
+            if (
+                hasattr(new_message, "tool_calls")
+                and new_message.tool_calls is not None
+            ):
                 new_tool_calls = self._process_tool_calls(new_message)
                 tool_calls.extend(new_tool_calls)
 
@@ -281,7 +284,7 @@ async def _process_model_response(self, res: ModelResponse):
         new_messages = self.messages
 
         new_message = res.choices[0].message
-        if new_message.tool_calls:
+        if hasattr(new_message, "tool_calls") and new_message.tool_calls is not None:
             new_tool_calls = self._process_tool_calls(new_message)
             tool_calls.extend(new_tool_calls)