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How to use AI for git commit messages

Q: How to use AI for git commit messages

Use an AI language model like gpt-4o to generate descriptive git commit messages by sending the diff or staged changes as input to the model via the chat.completions.create API. This automates writing clear commit messages that summarize code changes effectively.

Quick answer

Use an AI language model like gpt-4o to generate descriptive git commit messages by sending the diff or staged changes as input to the model via the chat.completions.create API. This automates writing clear commit messages that summarize code changes effectively.

PREREQUISITES

Python 3.8+
OpenAI API key (free tier works)
pip install openai>=1.0

Setup

Install the OpenAI Python SDK and set your API key as an environment variable for secure access.

bash

pip install openai>=1.0

Step by step

This example shows how to generate a git commit message by sending the git diff output to the gpt-4o model using the OpenAI Python SDK.

python

import os
from openai import OpenAI
import subprocess

# Initialize OpenAI client
client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])

# Get the staged git diff
result = subprocess.run(["git", "diff", "--staged"], capture_output=True, text=True)
git_diff = result.stdout

# Prepare prompt for commit message generation
prompt = f"Generate a concise and clear git commit message for the following changes:\n\n{git_diff}" 

# Call the OpenAI chat completion endpoint
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": prompt}]
)

commit_message = response.choices[0].message.content.strip()
print("Generated commit message:")
print(commit_message)

output

Generated commit message:
Fix bug in user authentication flow by correcting token validation logic

Common variations

Use git diff without --staged to generate messages for unstaged changes.
Switch to asynchronous calls with asyncio for integration in larger apps.
Try other models like claude-3-5-sonnet-20241022 for potentially better commit message quality.
Incorporate commit message templates or prefixes by modifying the prompt.

Troubleshooting

If the commit message is too generic, provide more context in the prompt or include file names.
If API calls fail, verify your OPENAI_API_KEY environment variable is set correctly.
For very large diffs, truncate input or summarize changes before sending to the model to avoid token limits.

✅

Key Takeaways

Use the git diff output as input to an AI model to generate descriptive commit messages automatically.
The OpenAI gpt-4o model can produce concise, human-readable commit summaries from code changes.
Customize prompts and model choice to improve message relevance and style for your project.
Always secure your API key using environment variables and handle large diffs carefully to avoid token limits.

Verified 2026-04 · gpt-4o, claude-3-5-sonnet-20241022

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