This resonates

I've had success with greenfield code followed by frustration when asking for changes to that code due to over editing

And prompting for "minimal changes" does keep the edits down. In addition to this instruction, adding specifics about how to make the change and what not to do tends to get results I'm looking for.

"add one function that does X, add one property to the data structure, otherwise leave it as is, don't add any new validation"