git-rewrite-commits

$ npx git-rewrite-commits

AI-powered git commit message rewriter using AI

Automatically rewrite your entire git commit history with better, conventional commit messages using AI. Perfect for cleaning up messy commit histories before open-sourcing projects or improving repository maintainability.

📖 Read the blog post: Fix Your Messy Commit History with AI

Important Disclaimer

This tool rewrites git history, which is generally NOT recommended for shared repositories!

When to use:

• Personal projects before making them public
• Feature branches before merging (with team agreement)
• Cleaning up local commits before pushing
• Preparing repositories for open-sourcing

When NOT to use:

• On shared branches without team coordination
• After pushing commits that others have pulled
• On main/master branches of team projects
• In repositories where commit hashes are referenced

Remember: Rewriting history changes commit hashes and requires force-pushing, which can disrupt your team's workflow.

Security & Privacy

🔒 Important Privacy Notice: When using remote AI providers (OpenAI), this tool sends your file lists and diffs to external APIs.

Security Features:

• ✅ Explicit consent required before sending data to remote providers
• ✅ Automatic redaction of API keys, passwords, and private keys
• ✅ Local processing option via Ollama (no data leaves your machine)
• ✅ Opt-in hooks - all hooks require explicit enabling via git config
• ✅ Secure argument handling - prevents shell injection attacks
• ✅ Always creates backups before history rewrites

Recommended for sensitive repositories:

# Use local Ollama instead of remote APIs
git config hooks.commitProvider ollama
git config hooks.providerModel gemma3

ollama pull gemma3
ollama serve

📖 See SECURITY.md for complete security documentation

Features

• AI-powered commit message generation using OpenAI GPT or local Ollama models
• Rewrite entire git history with better commit messages
• Conventional commits format (feat, fix, chore, etc.)
• Multi-language support - generate commits in any language
• Smart filtering - skip already well-formed commits
• Local AI option with Ollama - no data leaves your machine
• Git hooks integration - automatic AI messages on every commit
• Intelligent analysis of code changes to generate meaningful messages
• Batch processing with rate limiting
• Safe operation with automatic backup branches
• Custom templates for team-specific formats
• Quality scoring to identify commits that need improvement
• Verbose mode with diff preview and detailed processing information
• Custom prompts - Override AI behavior with --prompt for unique styles
• Efficient processing - Process only the last N commits with --max-commits
• Dry-run mode - Preview changes before applying them
• Progress tracking - Real-time progress indicators with colored output
• Custom context - Project-specific guidelines via COMMIT_MESSAGE.md file

Installation

Quick Start (No Installation Required)

npx git-rewrite-commits
# or shorter:
npx grec

Global Installation

# Full command name
npm install -g git-rewrite-commits

# Or install the short alias (grec = git-rewrite-commits)
npm install -g grec

# Both work identically:
git-rewrite-commits --help
grec --help  # Same thing, just shorter!

✅ Works on all platforms: Windows, macOS, Linux
💡 Tip: grec is a shorter alias for git-rewrite-commits - use whichever you prefer!

Quick Hook Installation

Step 1: Install or update the AI commit message hooks

npx git-rewrite-commits --install-hooks
# or with the short alias:
npx grec --install-hooks

💡 Updates existing hooks: If hooks already exist, they'll be updated to the latest version. Non-git-rewrite-commits hooks are backed up before replacement.

Step 2: Enable the hooks you want (opt-in required for security):

# Option A: Enable message preview before commit
git config hooks.preCommitPreview true

# Option B: Enable automatic message generation
git config hooks.prepareCommitMsg true

# Or enable both for the full experience!

# For privacy: use local Ollama instead of remote OpenAI
git config hooks.commitProvider ollama
git config hooks.providerModel llama3.2  # Optional: specify model

Step 3: Configure your AI provider:

# Option A: OpenAI (sends data to remote API)
export OPENAI_API_KEY="your-api-key"  # Unix/macOS
# set OPENAI_API_KEY="your-api-key"    # Windows

# Option B: Ollama (local processing, recommended for sensitive repos)
ollama pull llama3.2
ollama serve

# Option C: Ollama on a custom server/port
export OLLAMA_URL="http://192.168.1.100:11434"  # Unix/macOS
# set OLLAMA_URL=http://192.168.1.100:11434     # Windows

See QUICK_START.md for detailed setup guide

Additional Configuration (Optional)

# Set your template format
git config hooks.commitTemplate "[JIRA-XXX] feat: message"

# Set language
git config hooks.commitLanguage "es"  # Spanish, French, etc.

# Set specific model
git config hooks.providerModel "gpt-4"  # or "gpt-3.5-turbo", "llama3.2", etc.

# Set custom Ollama server URL (if not using localhost:11434)
git config hooks.ollamaUrl "http://192.168.1.100:11434"

Custom Project Guidelines with COMMIT_MESSAGE.md

You can provide project-specific commit message guidelines that the AI will follow by creating a COMMIT_MESSAGE.md file. The tool searches for this file in the following locations (in order):

• Project root - ./COMMIT_MESSAGE.md
• Git directory - ./.git/COMMIT_MESSAGE.md
• GitHub directory - ./.github/COMMIT_MESSAGE.md

Example COMMIT_MESSAGE.md:

# Project Commit Guidelines

## Requirements
- Use conventional commits with these scopes: auth, api, ui, db
- Include ticket numbers when available (e.g., JIRA-123)
- Security changes must be clearly marked
- Breaking changes need BREAKING CHANGE in the message

## Project Context
This is a financial services API that handles sensitive data.
Emphasize security, compliance, and performance in commit messages.

See COMMIT_MESSAGE.md.example in this repository for a complete example.

Usage

Command Examples

# Using the full command name
npx git-rewrite-commits [options]

# Or using the short alias (grec)
npx grec [options]

Common use cases:

# Rewrite entire git history
npx git-rewrite-commits

# Preview changes without applying (dry run)
npx git-rewrite-commits --dry-run

# Generate commit message for staged changes
npx git-rewrite-commits --staged

# Process only last 10 commits
npx git-rewrite-commits --max-commits 10

# Use custom AI model
npx git-rewrite-commits --model gpt-4

# Use local AI with Ollama
npx git-rewrite-commits --provider ollama

# Install/update git hooks
npx git-rewrite-commits --install-hooks

Real-World Examples

Automatic Commit Message Generation

Two Smart Hooks:

• pre-commit: Preview AI message and optionally replace bad commit messages
• prepare-commit-msg: Automatically generate or use approved messages

# Install the hooks (using either command)
npx git-rewrite-commits --install-hooks
# or
npx grec --install-hooks

# Enable them (opt-in for security)
git config hooks.preCommitPreview true    # Preview before commit
git config hooks.prepareCommitMsg true    # Auto-generate in editor

# Configure provider
git config hooks.commitProvider ollama  # or use OpenAI with OPENAI_API_KEY
git config hooks.providerModel llama3.2  # Optional: specify model

Now when you run git commit:

• With pre-commit: You'll see a preview of the AI message first
• With prepare-commit-msg: The AI message appears in your editor

Manual Rewriting for Existing Commits

# Clean up the last 5 commits before pushing
echo "🔧 Improving commit messages before push..."
npx git-rewrite-commits --max-commits 5 --dry-run

echo "Apply changes? (y/n)"
read answer
if [ "$answer" = "y" ]; then

Alias for Quick Fixes

Add to your ~/.gitconfig or ~/.zshrc/~/.bashrc:

# Git alias
git config --global alias.fix-commits '!npx git-rewrite-commits --max-commits'

# Usage: git fix-commits 3

# Shell alias
alias fix-last-commit='npx git-rewrite-commits --max-commits 1 --skip-backup'
alias fix-branch='npx git-rewrite-commits --max-commits 20'

# Usage: fix-last-commit

Team Workflow: Feature Branch Cleanup

Before creating a pull request:

# 1. Check what needs fixing
npx git-rewrite-commits --dry-run --max-commits 10

# 2. Apply improvements
npx git-rewrite-commits --max-commits 10

# 3. Force push to your feature branch
git push --force-with-lease origin feature-branch

CI/CD Integration

Add to your CI pipeline (e.g., GitHub Actions) for PR validation:

- name: Check Commit Quality
  run: |
    npx git-rewrite-commits --dry-run --max-commits ${{ github.event.pull_request.commits }}
    # This will show which commits would be improved

Preparing for Open Source

Before making a private repo public:

# Fix all commits with custom template
npx git-rewrite-commits \
  --template "feat(scope): message" \
  --language en \
  --no-skip-well-formed

# Review the changes
git log --oneline -20

# If satisfied, force push
git push --force-with-lease origin main

How It Works

• Analyze: Reads your staged changes or commit history
• Generate: Uses AI to create meaningful, conventional commit messages
• Apply: Updates your commits with better messages

Smart Message Replacement

When you use git commit -m "bad message", pre-commit can:

• Suggest a better AI-generated message
• Replace your bad message when you approve it
• Show what was replaced in the commit editor

History Rewriting Process

• Creates backup: Saves current branch state
• Rewrites history: Uses git filter-branch to apply new messages
• Provides recovery: Keeps backup branch for restoration if needed

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

• Fork the repository
• Create your feature branch (git checkout -b feature/AmazingFeature)
• Commit your changes (using conventional commits!)
• Push to the branch (git push origin feature/AmazingFeature)
• Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Bug Reports

If you discover any bugs, please create an issue here.

Contact

For questions and support, please open an issue in the GitHub repository.

Remember: Always backup your repository before rewriting history! 🔒