I'm not sure if agents are better or worse than humans at refactoring.

When they get it right, it works well - full context covered, full business logic recreated completely.

When they fail, they fail fairly hard. They miss some functions in a grep, or return too many and fail to address one part, and they end up with holes.

I scrutinise the work heavily, and find I rely on gut feel a lot for what's right and wrong.