Show HN: Cmtly – turns staged Git diff into a polished commit message

cmtly is a lightweight CLI that turns your staged Git diff into a polished commit message. It taps into Apple Foundation Models to summarize the diff, then copies a ready-to-run git commit command to your clipboard. Stage your changes, run cmtly, and commit with confidence. ✨

• macOS 15 or newer (Apple Foundation Models require it)
• Xcode Command Line Tools (xcode-select --install)
• Git installed and available on your PATH

Run the installer script:

The script builds cmtly, installs the binary at ~/.cmtly/bin/cmtly, and reminds you to add the directory to your PATH so the command is available in future shells.

Pick the snippet for your shell and run it once:

• zsh → echo 'export PATH="$HOME/.cmtly/bin:$PATH"' >> ~/.zshrc
• bash → echo 'export PATH="$HOME/.cmtly/bin:$PATH"' >> ~/.bash_profile
• fish → set -U fish_user_paths $HOME/.cmtly/bin $fish_user_paths

After updating your profile, restart the terminal (or source the file) and verify:

1. Stage your changes: git add .
2. Generate a message: cmtly
3. Review the summary, then paste the copied git commit command (already added to your clipboard) and hit enter ✅

cmtly exits with a descriptive message if:

• You are outside a Git repository
• No staged changes are detected
• The Apple Foundation Model service is unavailable

• cmtly not found: Ensure ~/.cmtly/bin appears in echo $PATH and that you restarted your shell.
• Model availability errors: Make sure you are on macOS 15+ and signed into an Apple ID that can access Foundation Models.
• Git errors: Confirm Git is installed and that you are inside a repository with staged changes.

Happy committing! 💚