I made a /split-commit prompt that automatically splits a megacommit into smaller commits. I've found this massively helpful for making more reviewable commits. You can either run this yourself or send this to your coworker to have them run it before asking you to re-review it.

Sometimes it doesn't split it among optimal boundaries, but it's usually good enough to help. There's probably room for improvement and extension (eg. re-splitting a branch containing many not-logical commits, moving changes between commits, merging commits, ...) – contributions welcome!

You can install it as a Claude Code plugin here: https://github.com/KevinWuWon/kww-claude-plugins (or just copy out the prompt from the repo into your agent of choice)