[Bug] ChainOfThoughtWithHint is broken (at least for Azure)

[chrico-bu-uab]

What happened?

WARNING dspy.adapters.json_adapter: Failed to use structured output format. Falling back to JSON mode. Error: litellm.BadRequestError: AzureException BadRequestError - Unknown parameter: 'rationale_type'.

Steps to reproduce

any signature should reproduce the error

DSPy version

2.6.23

[Ankit3794]

failing for direct OpenAI call also

Original error: litellm.BadRequestError: OpenAIException - Unrecognized request argument supplied: rationale_type.

[ManuelRios18]

Same problem!

Have you guys any updates on this?

[rafsid]

use dspy==2.6.19. I was using the latest and i kept on downgrading one version at a time.

it looks like downgrading dspy to 2.6.19 (which also brought in older versions of litellm and openai) resolved the compatibility issues you were facing with the Gemini API and structured output.
It's not uncommon for rapid developments in libraries like DSPy and LiteLLM, and changes in how they interact with various model provider APIs, to sometimes lead to temporary incompatibilities or require specific version combinations to work smoothly, especially with newer or preview models.

[Hangzhi]

@chenmoneygithub the error Original error: litellm.BadRequestError: OpenAIException - Unrecognized request argument supplied: rationale_type. is fixed in #8382. Can you help take a look?