autogen/dotnet/website/articles/OpenAIChatAgent-use-json-mode.md
What is JSON mode? JSON mode is a new feature in OpenAI which allows you to instruct model to always respond with a valid JSON object. This is useful when you want to constrain the model output to JSON format only.  > [!NOTE] > Currently, JOSN mode is only supported by `gpt-4-turbo-preview` and `gpt-3.5-turbo-0125`. For more information (and limitations) about JSON mode, please visit [OpenAI API documentation](https://platform.openai.com/docs/guides/text-generation/json-mode). 