Commit Message Generation

VCS Detection

FIRST: Detect which VCS this repo uses:

[[ -d .jj ]] && echo "JJ" || echo "GIT"

Getting Changes

If JJ repo:

jj diff  # shows current changes
jj log -r @  # shows current change description

If Git repo:

git diff --staged  # for staged changes
git diff  # for unstaged changes
git status  # context on what's changed

Message Format

Generate messages with:

1. Summary (under 50 chars, present tense)
2. Detailed description (why + what, not how)
3. Affected components if relevant

Style:

• Present tense ("Add feature" not "Added feature")
• Explain why the change matters
• Reference file:line for key changes
• Keep it human-readable

Never include:

• Co-author tags (especially not yourself)
• Thread IDs or internal agent metadata
• Generic fluff like "fixes bug" without context

Example

Add user authentication timeout handling

Users were getting stuck in limbo when auth tokens expired during
long sessions. Now we detect expiration and prompt re-login.

- auth/session.go:42 - token expiration check
- ui/Login.tsx:18 - re-login prompt

Workflow

For JJ repos:

1. Show current diff with jj diff
2. Suggest message
3. User runs: jj describe -m "your message"

For Git repos:

1. Show staged changes with git diff --staged
2. Suggest message
3. User runs: git commit -m "your message"

Do not automatically commit unless explicitly requested.