ai-prepare-commit-msg

How the Hook Works

ai-prepare-commit-msg connects Git’s prepare-commit-msg lifecycle to a language model through LiteLLM.

The design goal is simple: you keep your normal commit flow, and the tool proposes a high-quality draft based on staged changes.

Lifecycle Integration

Git runs prepare-commit-msg before the commit message editor opens. This project uses that moment to inspect staged diffs, send a prompt to the selected model, and write a suggested commit message to the commit message file.

You stay in control. The generated output is a draft, and you can edit it before the commit is finalized.

Why LiteLLM

LiteLLM provides a single abstraction over multiple providers. That means you can switch models by changing environment variables, instead of rewriting hook logic.

Prompt Strategy

The prompt files define the writing constraints, including Conventional Commits alignment and style expectations. This keeps behavior consistent across model providers.

Operational Model

Input: staged diff and context.
Processing: prompt rendering and model inference.
Output: commit message draft inserted into Git’s message buffer.

This model keeps the integration narrow, which makes the hook easy to install, reason about, and replace.