Reasoning response support

[samuelcolvin]

See:

• OpenAI reasoning docs
• Deepseek reasoning docs
• Gemini "thinking" docs

No idea yet how this should look, but we should try to support it.

[Wh1isper]

I've used some pretty tricky ways to implement reasoning in the pydantic-ai-bedrock package: ai-zerolab/pydantic-ai-bedrock#15

Based on this practice, I think we need to add a ReasoningPart, and then the Model will implement the object transformation based on that. On top of that, we need to think about how the Agent is returned, perhaps using the <Thinking> tag would be better?

[soichisumi]

I would like to request support for Claude's Extended thinking.
While it may be difficult to be compatible with other models, this feature provides robust and flexible thinking and integration with tool use.
https://docs.anthropic.com/en/docs/build-with-claude/extended-thinking?q=thinking#how-extended-thinking-works

[arty-hlr]

Maybe openrouter's reasoning tokens should also be added: https://openrouter.ai/docs/use-cases/reasoning-tokens for people who use Claude 3.7 through it for example. At the moment no reasoning is shown.

[arty-hlr]

Link to relevant slack conversation:
https://pydanticlogfire.slack.com/archives/C083V7PMHHA/p1743405703872439

[pedroallenrevez]

Any news on this?

[brycedrennan]

I want to use pydantic-ai at work but not being able to use reasoning models is one of the things holding me back.