"Letting the agents loop can result in more changes than expected, which are usually welcome..." If "more changes than expected" means "out of scope", then I disagree. Those types of changes are exactly one of the things that's best to avoid whether code is being written by a person or an LLM.
That’s why I’m wondering if we should instruct the agents to act more like humans would: if the change can be done in a follow-up PR, this is probably what an experienced engineer would do.