backward compatibility

Author: braisedpork1964

lagent/agents/agent.py

@@ -73,7 +73,10 @@ def __call__(self, *message: AgentMessage, session_id=0, **kwargs) -> AgentMessa
         self.update_memory(message, session_id=session_id)
         response_message = self.forward(*message, session_id=session_id, **kwargs)
         if not isinstance(response_message, AgentMessage):
-            response_message = AgentMessage.from_model_response(response_message, self.name)
+            if isinstance(response_message, str):
+                response_message = AgentMessage(sender=self.name, content=response_message)
+            else:
+                response_message = AgentMessage.from_model_response(response_message, self.name)
         self.update_memory(response_message, session_id=session_id)
         response_message = copy.deepcopy(response_message)
         for hook in self._hooks.values():
@@ -208,7 +211,10 @@ async def __call__(self, *message: AgentMessage, session_id=0, **kwargs) -> Agen
         self.update_memory(message, session_id=session_id)
         response_message = await self.forward(*message, session_id=session_id, **kwargs)
         if not isinstance(response_message, AgentMessage):
-            response_message = AgentMessage.from_model_response(response_message, self.name)
+            if isinstance(response_message, str):
+                response_message = AgentMessage(sender=self.name, content=response_message)
+            else:
+                response_message = AgentMessage.from_model_response(response_message, self.name)
         self.update_memory(response_message, session_id=session_id)
         response_message = copy.deepcopy(response_message)
         for hook in self._hooks.values():