I just had very bad JSON mode operation with gemini-1.5-flash and 2.0-flash models using their own library 'google-generativeai'. Either can't follow JSON formatting correctly, or renders string fields with no end until max_tokens. Pretty bad for Gemini, when open models like Qwen do a better job of a basic information extraction to JSON task.
Things to note:
1) supply a JSON schema in `config.reponse_schema`
2) set the `config.response_type` to `application/json`
That works for me reliably. I've had some issues with running into max_token constraints but that was usually on me because I had let it process a large list in one inference call, which would have resulted in very large outputs.
We're using gemini JSON mode in production applications with both `google-generativeai` and `langchain` without issues.
