Mechanism to use a different model from the same provider

[swerner]

For example, being able to optionally choose between using gpt-3.5 for something, using gpt-4-turbo for others, or between using claude-haiku for some and claude-opus for others if you want, but for the majority of cases being able to mostly rely on the defaults.

[swerner]

Maybe this makes sense to put in the output adapter rather than the generator? Some other thing? It seems tied to the output and/or input to figure out which model (and maybe) which provider to use?