Commit GPT

A CLI that writes your git commit messages for you with AI. Never write a commit message again.

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Installation

Prerequisites: Install Ruby

If you don't have Ruby installed, follow these steps first.

macOS

1. Install Homebrew (skip if already installed)

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
echo 'export PATH="/opt/homebrew/bin:$PATH"' >> ~/.zshrc
source ~/.zshrc

2. Install Ruby dependencies

brew install openssl@3 libyaml gmp rust

Ubuntu / Debian

Install Ruby dependencies

sudo apt-get update
sudo apt install build-essential rustc libssl-dev libyaml-dev zlib1g-dev libgmp-dev

Install Ruby with Mise (version manager)

# Install Mise
curl https://mise.run | sh

# For zsh (macOS default)
echo 'eval "$(~/.local/bin/mise activate)"' >> ~/.zshrc
source ~/.zshrc

# For bash (Ubuntu default)
# echo 'eval "$(~/.local/bin/mise activate)"' >> ~/.bashrc
# source ~/.bashrc

# Install Ruby
mise use --global ruby@3

# Verify installation
ruby --version
#=> 3.4.7

# Update RubyGems
gem update --system

Install CommitGPT

gem install commitgpt

Usage

API Key

Grab your API key and add it as an env variable.

$ export AICM_KEY=sk-xxxxxxxxxxxxxxxx

It's recommended to add this to your .zshrc or .bashrc so it persists across terminal sessions.

Custom API Endpoint (Optional)

You can use any OpenAI-compatible API provider by setting AICM_LINK:

# Default
$ export AICM_LINK=https://api.openai.com/v1

# Use a local proxy
$ export AICM_LINK=http://127.0.0.1:8045/v1

# Or use another provider
# Cerebras
$ export AICM_LINK=https://api.cerebras.ai/v1

# Groq
$ export AICM_LINK=https://api.groq.com/openai/v1

Note: If you're using a local proxy that doesn't require authentication, you can leave AICM_KEY empty.

List Models

Use -m to list all available models from your API provider:

$ aicm -m
llama3.1-8b
llama-3.3-70b
gpt-4o-mini

aicm

aicm is an abbreviation for AI commits. After staging your changes with git add ., use aicm to commit with an AI-generated message.

$ cd /path/to/your/repo
$ git add .
$ aicm

▲ Welcome to AI Commits!
▲   Generating your AI commit message...

▲ Commit message: git commit -am "Update README.md with contribution instructions and OpenAI API key instructions."

▲ Do you want to commit this message? [y/n]
[main c082637] Update README.md with contribution instructions and OpenAI API key instructions.
 4 files changed, 24 insertions(+), 19 deletions(-)

Update

To update to the latest version:

$ gem update commitgpt
$ gem cleanup commitgpt
$ gem info commitgpt

Configuration

Environment Variable	Required	Default	Description
AICM_KEY	No*	nil	Your API key. Required when using official OpenAI API.
AICM_LINK	No	https://api.openai.com/v1	Custom API endpoint for OpenAI-compatible services.
AICM_MODEL	Yes	gpt-4o-mini	Model to use for generating commit messages.
AICM_DIFF_LEN	No	32768	Maximum diff length in characters. Increase if you have large diffs.

* Required when using the default OpenAI endpoint.

Available Models

Use aicm -m to list models from your provider, or set AICM_MODEL directly:

OpenAI (https://api.openai.com/v1)

gpt-5.2 
gpt-5-mini 
gpt-5-nano 
gpt-4o-mini

Cerebras (https://api.cerebras.ai/v1) ⭐ Recommended

zai-glm-4.7          # ⭐ Best for commit messages - fast & accurate
zai-glm-4.6
gpt-oss-120b
llama3.1-8b
llama-3.3-70b
qwen-3-32b
qwen-3-235b-a22b-instruct-2507

Groq (https://api.groq.com/openai/v1)

llama-3.3-70b-versatile
llama-3.1-8b-instant
meta-llama/llama-4-maverick-17b-128e-instruct
meta-llama/llama-4-scout-17b-16e-instruct
qwen/qwen3-32b
moonshotai/kimi-k2-instruct-0905
openai/gpt-oss-120b
groq/compound
groq/compound-mini

How It Works

This CLI tool runs a git diff command to grab all staged changes, sends this to OpenAI's GPT API (or compatible endpoint), and returns an AI-generated commit message. The tool uses the /v1/chat/completions endpoint with optimized prompts for generating conventional commit messages.

Limitations

• Only supports git diffs up to AICM_DIFF_LEN characters (default 32K)
• The generated commit message can't be edited interactively, but you can choose n and copy the command to edit manually

Special Thanks

I used ChatGPT to convert AICommits from TypeScript to Ruby. Special thanks to https://github.com/Nutlope/aicommits

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ZPVIP/commitgpt. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

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

Code of Conduct

Everyone interacting in the CommitGpt project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.