JJ Commit Message Generator

Generate conventional commit messages for Jujutsu (jj) by analyzing diffs.

Instructions

When the user asks to create a commit message or commit changes:

1. •

   Run tests first:

   • •Detect test framework from project (package.json, Cargo.toml, pyproject.toml, etc.)
   • •Run appropriate test command:
     • •npm/yarn: npm test or yarn test
     • •Rust: cargo test
     • •Python: pytest or python -m pytest
     • •Go: go test ./...
   • •If tests fail:
     • •Show failures to user
     • •Ask: "Tests failing. Fix before commit, skip tests, or commit anyway?"
     • •Only proceed with commit if user explicitly chooses to skip/ignore
   • •If no test command found, proceed without testing
2. •

   Gather context:

   • •Run jj diff to see current changes
   • •Run jj log -r @ to see the current change description
   • •If working with specific revisions, use jj diff -r <revision>
3. •

   Analyze changes:

   • •Identify the type: feat, fix, refactor, docs, test, chore, style, perf
   • •Determine scope if clear from file paths
   • •Summarize the "why" (intent) not just "what" changed
4. •

   Generate message: Format: <type>(<scope>): <subject>

   • •Subject: imperative mood, lowercase, no period, < 72 chars
   • •Body (optional): explain why, not what
   • •Favor precision over verbosity

   Examples:

   • •feat(ui): add dark mode toggle
   • •fix(auth): prevent token refresh loop
   • •refactor(api): simplify error handling
5. •

   Handle immutable commits: If you get error: Commit ... is immutable:

   • •Explain that the commit is immutable
   • •Suggest running the command with --ignore-immutable flag
   • •Ask user if they want to proceed with the flag
6. •

   Execute commit:

   • •Use jj describe -m "message" for current change
   • •Or jj describe -r <revision> -m "message" for specific revision
   • •If immutable and user approves, add --ignore-immutable

Tool access

allowed-tools:

• •Bash
• •Read
• •Grep

Notes

• •Keep messages concise and clear
• •Focus on intent, not implementation details
• •Follow conventional commit format strictly