AI git commit message

A Ruby gem that automatically generates concise and meaningful git commit messages using a local LLM via Ollama, LM Studio, llama.cpp llama-server, or any other OpenAI-compatible API.

Installation

Install the gem using:

gem install ai-commit-message

Or add it to your Gemfile:

gem 'ai-commit-message'

And then run:

bundle install

Requirements

• Ruby 3.0 or newer
• Git repository
• A local LLM server: Ollama, LM Studio, llama.cpp llama-server, or any other OpenAI-compatible endpoint

Usage

Basic Usage

Generate a commit message for your staged changes and commit with it after a confirmation:

ai-commit-message commit

This will:

1. Analyze your staged changes (git diff --cached)
2. Review your recent commit history for style consistency
3. Consider your current branch name
4. Generate an appropriate commit message
5. Ask for confirmation and create the commit (answering "no" keeps the printed message so you can edit or copy it)

Message only

If you just want the suggested message without the confirmation prompt — e.g. to pipe it somewhere or review it yourself — use --message-only:

ai-commit-message commit --message-only

Conventional Commits

Ask the model to follow the Conventional Commits format (feat:, fix:, chore:, ...):

ai-commit-message commit --conventional

Configuration

Configure the API URL and model interactively:

ai-commit-message config

If your server is reachable, the model prompt becomes a picker populated with the models available on that server.

List the models available on your server:

ai-commit-message models

Command Line Options

Override configuration settings directly:

ai-commit-message commit --url=http://your-api-endpoint --model=your-model-name

All options:

Option	Description	Default
--url	Base URL of the OpenAI-compatible API	http://localhost:11434
--model	Model name	qwen3:8b
--length	Maximum message length in characters	72
--conventional	Use Conventional Commits format	off
--message-only	Print the message without the commit confirmation prompt	off

How It Works

The gem:

1. Collects your staged changes using git diff --cached (capped at 12,000 characters so large diffs don't overwhelm a local model's context)
2. Retrieves your recent commit history for context
3. Identifies your current branch name
4. Sends a chat request to {url}/v1/chat/completions — the standard OpenAI-compatible endpoint
5. Cleans the model output (strips code fences, quotes and reasoning blocks) and prints a single-line commit message (limited to 72 characters by default)

The URL accepts base addresses with or without a trailing /v1 and /, so http://localhost:11434 (Ollama), http://localhost:1234/v1 (LM Studio) and http://localhost:8080 (llama.cpp llama-server) all work as-is.

Configuration File

The gem stores your configuration in ~/.ai-commit-message.conf. You can manually edit this file if needed. Example:

url=http://localhost:11434
model=qwen3:8b

Models

The default configuration uses Ollama with the qwen3:8b model, but you can use any model available through your API endpoint.

Recommended Models

• qwen3:8b: Good balance of quality and speed (default). Note that it is a thinking model, so expect a few seconds of reasoning before the message appears
• qwen2.5-coder:7b: Faster, non-thinking coding model
• qwen3.5:4b: Current-generation small model for modest hardware
• gemma4:e4b: Compact general-purpose option
• llama3.1:8b: Solid general-purpose choice

Contributing

1. Fork the repository
2. Create your feature branch: git checkout -b my-new-feature
3. Install dependencies: bundle install
4. Run the tests: bundle exec rake test
5. Make your changes and add tests if applicable
6. Commit your changes: git commit -m 'Add some feature'
7. Push to the branch: git push origin my-new-feature
8. Submit a pull request

License

This gem is available as open source under the terms of the MIT License.