Coding agents pad their diffs to look thorough, and the padding is where the bugs hide

Coding agents often introduce unnecessary changes, or "padding," into their code diffs when fixing bugs. This padding can include reformatting, refactoring, or adding new dependencies, which frequently introduce new bugs into production environments. Reviewers often overlook these extraneous changes, focusing only on the intended fix. A key strategy to mitigate this issue is to implement a rule, such as "Rule 5," that forces agents to justify each code hunk, leading to the removal of unjustified changes before they are presented for review.

This report uniquely identifies "padding" in AI-generated code as a source of new bugs, unlike other discussions that focus solely on the correctness of the primary fix.