It's funny you say this! I was adding a tool just earlier (that I haven't yet pushed) that allows the model to... switch model.

Aider can also have multiple models active at any time (the architect, editor and weak model is the standard set) and use them for different aspects. I could definitely imagine switching one model whilst leaving another active.

So yes, this definitely seems feasible.

Aider had a fairly coherent answer to this question, I think: https://gist.github.com/tekacs/75a0e3604bc10ea88f9df9a909b5d...

This was navigator mode + Gemini 2.5 Pro's attempt at implementing it, based only on pasting in your comment:

https://asciinema.org/a/EKhno9vQlqk9VkYizIxsY8mIr

https://github.com/tekacs/aider/commit/6b8b76375a9b43f9db785...

I think it did a fairly good job! It took just a couple of minutes and it effectively just switches the main model based on recent input, but I don’t doubt that this could become really robust if I had poked or prompted it further with preferences, ideas, beliefs and pushback! I imagine that you could very quickly get it there if you wished.

It's definitely not showing off the most here, because it's almost all direct-coding, very similar to ordinary Aider. :)