@light-cat/ai-commit-msg

AI-powered commit message generator for git. Automatically generates conventional commit messages based on your staged changes.

Features

• 🤖 AI-powered: Uses AI to analyze your code changes and generate meaningful commit messages
• 📝 Conventional Commits: Follows the Conventional Commits format
• 🔧 Easy Configuration: Simple .env setup with environment variable support
• 🛡️ Safe: Doesn't block commit on errors - falls back gracefully
• 🔌 OpenAI Compatible: Works with OpenAI, Azure OpenAI, and any OpenAI-compatible API
• ⚡ CLI Ready: Can be used directly with pnpm exec or installed globally

Installation

Local Installation (Recommended)

# With npm
npm install --save-dev @light-cat/ai-commit-msg

# With pnpm
pnpm add --save-dev @light-cat/ai-commit-msg

# Set up git hooks (installs simple-git-hooks if needed)
pnpm exec ai-commit setup

Global Installation

# With npm
npm install -g @light-cat/ai-commit-msg

# With pnpm
pnpm add -g @light-cat/ai-commit-msg

# Then set up git hooks in your project
cd /path/to/your/project
pnpm exec ai-commit setup

Configuration

Create a .env file in your project root or set environment variables:

# Required
AI_API_KEY=your-api-key-here

# Optional (defaults shown)
AI_API_BASE_URL=https://api.openai.com/v1
AI_MODEL=gpt-4

Supported AI Providers

| Provider | AI_API_BASE_URL | AI_MODEL | |----------|-------------------|------------| | OpenAI | https://api.openai.com/v1 | gpt-4, gpt-3.5-turbo | | Azure OpenAI | Your Azure endpoint | Your deployment name | | Local/Other | Your custom endpoint | Any OpenAI-compatible model |

Getting API Keys

• OpenAI: Get your API key from platform.openai.com

Usage

Basic Usage

After setting up the git hook, simply commit your changes without providing a message:

# Stage your changes
git add .

# Commit - AI will automatically generate a commit message
git commit

The tool will:

1. Fetch staged changes
2. Send them to the AI service
3. Generate a conventional commit message
4. Write it to the commit message file

Automatic Setup

# Install hooks and configure simple-git-hooks automatically
pnpm exec ai-commit setup

Manual Setup (if you already have simple-git-hooks)

Add to your package.json:

{
  "simple-git-hooks": {
    "prepare-commit-msg": "pnpm exec ai-commit"
  }
}

Or if using lefthook:

# lefthook.yml
pre-commit:
  commands:
    generate-commit-msg:
      run: pnpm exec ai-commit

Standalone Usage

# Dry run (show message without writing)
pnpm exec ai-commit --dry-run

# Verbose mode (show debug info)
pnpm exec ai-commit --verbose

# Help
pnpm exec ai-commit --help

How It Works

1. When you run git commit, the prepare-commit-msg hook is triggered
2. The tool fetches:
   • Staged changes (git diff --cached)
   • Current branch name
   • Last commit message (if available)
3. Sends this information to the AI service
4. Generates a conventional commit message
5. Writes it to the commit message file

Example

Given this staged change:

diff --git a/src/auth.ts b/src/auth.ts
+export function validateEmail(email: string): boolean {
+  return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);
+}

The tool might generate:

feat(auth): add email validation function

Troubleshooting

"AI_API_KEY is not set"

Make sure your .env file exists and contains AI_API_KEY, or set the environment variable before committing.

Commit message not being generated

1. Check if changes are staged (git add first)
2. Run with --verbose to see debug information
3. Ensure your API key has sufficient credits/permissions
4. Verify git hooks are installed: cat .git/hooks/prepare-commit-msg

Want to use a custom message?

Simply provide a commit message when running git commit -m "your message" - the tool will detect an existing message and skip generation.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Local Development

Debugging

1. Direct Source Execution

Run the source code directly with tsx (recommended for ESM projects):

cd /path/to/node-ai-commit
pnpm tsx bin/ai-commit.js --help

Or using the dev script:

pnpm dev -- --help

Note: ts-node has limited ESM support. Use tsx instead for better compatibility.

2. Using npm link

Link the local package globally and test in other projects:

cd /path/to/node-ai-commit
pnpm link

# In another project
cd /path/to/your-project
pnpm link @light-cat/ai-commit-msg
pnpm exec ai-commit setup

3. Local Path Installation

In another project's package.json:

{
  "devDependencies": {
    "@light-cat/ai-commit-msg": "link:/path/to/node-ai-commit"
  }
}

Then run pnpm install or npm install in that project.

4. Build and Test

# Build the TypeScript
pnpm build

# Run locally (requires build first)
node bin/ai-commit.js --help

# Or run directly without building
pnpm tsx bin/ai-commit.js --help

Testing Setup

1. Create a test repository:

mkdir test-ai-commit && cd test-ai-commit
git init

2. Link the local package:

cd /path/to/node-ai-commit
pnpm link --global

cd /path/to/test-ai-commit
pnpm link --global @light-cat/ai-commit-msg

3. Set up and test:

# Create .env with your API key
pnpm exec ai-commit setup

# Make some changes and commit (don't provide message, let AI generate it)
git add .
git commit