Gemini 2.0 flash thinking exp is failing for JSON Mode

Google AI Studio
1

Code:
generation_config = {
“temperature”: 1,
“top_p”: 0.95,
“top_k”: 64,
“max_output_tokens”: 8192,
“response_mime_type”: “application/json”,
“response_schema”: {
“type”: “object”,
“properties”: {
“is_true_statement”: {“type”: “boolean”},
“is_completely_final_answer”: {“type”: “boolean”},
“reply”: {“type”: “string”},
},
“required”: [“is_true_statement”, “is_completely_final_answer”, “reply”]
}

    model = genai.GenerativeModel(
        # model_name="gemini-1.5-flash",
        # model_name="gemini-1.5-pro",
        model_name="gemini-2.0-flash-thinking-exp-1219",
        generation_config=generation_config,
        system_instruction=system_message
    )
    if not session:
        session = model.start_chat(
            history=chat_history
        )

    parts = []
    if file_part:
        parts.append(file_part)
    parts.append(Part(text=user_chat_input))
    content = Content(role="user", parts=parts)
    gemini_response = session.send_message(content)

Error:
google.api_core.exceptions.InvalidArgument: 400 Json mode is not enabled for models/gemini-2.0-flash-thinking-exp-1219

2 Likes
3

Getting the same thing here

1 Like
5

Continuing the discussion from Gemini 2.0 flash thinking exp is failing for JSON Mode:

@Angelo_Cortez Attempt this again after ensuring your code is clean.

7

JSON mode is not expected to work in Gemini 2.0 flash. The limitations section of thinking mode documentation mentioned that there is no built-in tool usage, and text only output. The documentation will be updated to make it clearer.