I am using the web interface but I get the same issue via the API with openai native tools defined.
I enable all the tools on the side panel. But the function call is in the response body instead of in the tool_calls in the json.
Prompt: whats the current weather in london?
Response:
I'll check the current weather in London for you.
<function_calls> London celsius </function_calls>
In vllm it might need the tool parser set when starting:
vllm serve <model> --enable-auto-tool-choice --tool-call-parser deepseek_v3