It's not enabled by default for their function calling API. So, hallucination is possible. You have to set 'strict' to True manually to use the same grammar-ba

It's not enabled by default for their function calling API. So, hallucination is possible. You have to set 'strict' to True manually to use the same grammar-based sampling they use for structured outputs. https://platform.openai.com/docs/guides/function-calling?api-mode=responses#strict-mode https://platform.openai.com/docs/guides/function-calling?api...