A tool for cleaning up agent-written commit messages

Simon Willison’s commit-rewriter provides a small web interface for editing Git commit messages. He built it to remove agent-generated clutter and private issue references before a release. The tool creates a backup branch before rewriting history. Editing a message changes commit identities, so changes to shared branches still need coordination.

Simon Willison · Sep 14, 2026

Why it matters

Relevant when turning agent-assisted work into a history that teammates or open-source users can understand.

More context

The broader habit is to review commit messages as carefully as code. Check whether they describe the resulting change, expose private references, or contain irrelevant process chatter. Inspect the tool before using it on a repository.

Keep in mind

Rewriting commits changes history. A backup branch helps recovery, but collaborators still need coordination when published history changes.

Original read