adding model_dump_json()

agents-api/agents_api/routers/sessions/session.py

@@ -190,8 +190,7 @@ async def run(
         # Ref: https://github.com/openai/openai-cookbook/blob/main/examples/How_to_call_functions_with_chat_models.ipynb
         if not message.content and message.tool_calls:
             role = "function_call"
-            function_call = message.tool_calls[0].function.model_dump()
-            content = json.dumps(function_call)
+            content = message.tool_calls[0].function.model_dump_json()
 
         elif not message.content:
             raise ValueError("No content in response")