llm is a lot about the Python API (or SDK) as well: https://llm.datasette.io/en/stable/python-api.html

It shows how to use it async or sync, and even handles using async in a sync context.

It's hard to write a good CLI without also writing most of a Python API, and llm went the rest of the way by documenting it. I think llm has the best docs of the Python API of the three.