Avoid feature creep

The request sets the scope. Everything the diff contains should trace back to a sentence in the ask. Anything else is a suggestion, not a change.

The core rule

Build what was asked. Not what would be nice, not what a senior engineer would also do, not what the codebase "should" have. If a line of the diff cannot be justified by the request, it does not belong in the diff.

This applies to product scope and to code scope. A PRD that grows past its problem statement has the same disease as a bug fix that ships with a refactor.

Signals that creep is starting

Stop when you notice any of these: