> Open source thrives on all the different use cases the original author never personally ran into.

That's what issue trackers are meant to capture.

I could see maintainers wanting to take sole control over the code, and rather than swatting down PRs they can just guide AI to fix reported issues themselves, and merge what they approve of. Cut out the middle men.

The maintainer doesn't have to prompt the feature. The maintainer needs your prompt and the discussion around the prompt. He doesn't need your code. In fact, I would say that for open source projects, the prompt should go through the project's own software factory.