Show HN: Git Auto Commit (GAC) – LLM-powered Git commit command line tool

39 pointsposted 5 hours ago
by merge-conflict

28 Comments

cypriss9

3 hours ago

There's three types of people: those who already write excellent commit messages explaining the why, those who write decent ones explaining the what, and those who write garbage commit messages. Empirically, the first set is small. This tool will help the middle type be more efficient, and help the last type drastically.

Well done OP.

martinohansen

3 hours ago

I don’t get these kind of tools. A commit should be the why of a change, not a summary of what it is, anyone can either get that themselves or just read the code if they desire. What you can not get from the code is the _why_ which only you as the author can put.

derwiki

3 hours ago

I often start a change by having Cursor read the Slack thread (via MCP) that is motivating the change. In the same Cursor thread, after making the change, it has fairly good context on the _why_ and writes a helpful commit message.

therein

2 hours ago

Very nice, the fewer neurons you use the better. In biology they call it use it and lose it if my memory serves me correctly.

Neurons that fire together, fry together.

nvartolomei

3 hours ago

I do often ask Claude Code or Gemini CLI to write commits. I agree with you on why being important. Majority of these being bug fixes accompanied tests where the why is easily inferred from the change/newly added tests and their comments.

nicksergeant

4 hours ago

Neat project. If you're looking for something simpler just to use w/ Claude Code, a simple call to "claude -p" can work: https://github.com/nicksergeant/dotfiles/blob/master/zshrc#L...

merge-conflict

4 hours ago

Thanks! Can definitely do that, but GAC is faster than calling claude or another agent as they will take multiple api calls to look at git status, git diffs, etc. vs a single api call with GAC. Plus, GAC won't eat up your weekly limits! ;)

nicksergeant

4 hours ago

Oh I just pipe the diff into the Claude prompt, so it's only the one call.

bangaladore

an hour ago

> Automatic secret detection: Scans for API keys, passwords, and tokens before committing

Surely this is done on-device right? Or is the prompt asking the LLM if there are secrets in the changes.

Arguably I trust Github / Gitlab / etc more than OpenAI / Anthropic / etc

merge-conflict

an hour ago

The scanning is done on-device. I should've worded it better and said that it scans before any API calls. Too late to edit the post, unfortunately.

ClimaxGravely

an hour ago

Maybe it's because these days I use perforce more than git but I tend to find myself writing 80% of my commit message before I write any code and touch it up a little at the end.

paulirish

2 hours ago

Chiming in with my alternative, like others' but uses simonw's `llm`:

    git upstream-diff | llm --system-fragment cl-description.md
However, in practice, I notice the generated messages focus more on the what than the why. So it's rare I use them verbatim.

ah27182

3 hours ago

I've been using LMStudio to run a local LLM (Qwen3-4B) to generate commit messages using this command:

```

git diff --staged --diff-filter=ACMRTUXB | jq -Rs --arg prompt 'You are an assistant that writes concise, conventional commit messages. Always start with one of these verbs: feat, fix, chore, docs, style, refactor, test, perf. Write a short!! message describing the following diff:' '{model:"qwen/qwen3-4b-2507", input:($prompt + "\n\n" + .)}' | curl -s http://localhost:1234/v1/responses -H "Content-Type: application/json" -d @- | jq -r ".output[0].content[0].text"

```

rwdf

3 hours ago

"gac" is giving me PTSD flashbacks from having to deal with the "Global Assembly Cache" aeons ago.

glitch253

3 hours ago

Hey all - disclaimer I'm one of Cell's friends and encouraged them to release their utility on Pypi for others. It quickly became one of my favorite tools that I use every day.

`git commit` is gone, `uvx gac` is in!

avinash-iitb

4 hours ago

I like that you’ve added secret detection and multi-provider support — that’s something most LLM commit tools miss. Have you benchmarked latency differences between local models (like Ollama) and OpenAI/Anthropic? Would be interesting to see a speed comparison.

alwillis

4 hours ago

Hate writing commit messages.

Just installed gac; they nailed the UI/UX.

And so far, it works quite well.

merge-conflict

4 hours ago

Thank you! I used a combination of the questionary and click python libraries for the ui/ux.

acoliver

5 hours ago

Oh nice. Man I hate filling out all that stuff. And getting the LLM to do it without freestyling and hallucinating is a pain. Kinda wish it were an MCP so I can shove it in my CLI or maybe the hooks for git...

merge-conflict

5 hours ago

I'm considering making it optionally work as an MCP server!

adrianbooth17

4 hours ago

Very neat little project, I look forward to trying this

bigwheels

4 hours ago

aicommit2 works great: https://github.com/tak-bro/aicommit2

Getting started is as easy as installing claude/codex/gemini: npm install -g aicommit2

I'm excited to give gac a try and see how it stacks up! The steering hints with gac might give it an edge.

seba_dos1

4 hours ago

This misses the point of what a good commit message is so much that it could be a delightful satire.

jacobsenscott

4 hours ago

Yeah - if these are better than your current commit messages, just don't write commit messages. Anyone can read the code.

acoliver

3 hours ago

side-eye "anyone can read the code" -- usually the first words of someone who writes unreadable code. perl -e'$_=q/dk|jk`%fdk%w`da%qm`%fja`/;s/./chr(ord($&)^5)/seg;print'