Commit Message

The commit-message skill generates clear, conventional commit messages from diffs. It is designed for piped input (--stdin) and non-interactive workflows, making it ideal for shell aliases and Git hooks.

SKILL.md Overview

The skill defines:

Conventional Commits format — <type>(<scope>): <subject> with an optional body
Type vocabulary — feat, fix, refactor, docs, test, chore, perf, style
Rules — 72-char subject lines, imperative mood, explain “why” not “what”
Split guidance — If multiple logical changes are detected, suggest separate commits

commit-message/
└── SKILL.md

Basic Usage

Run from GitHub

Run the official example directly from the docs:

skillx run github:skillx-run/skillx/examples/skills/commit-message "Generate a commit message for my staged changes"

Run from a Local Clone of this Repository

If you are working inside a clone of skillx-run/skillx, use the repository path:

skillx run ./examples/skills/commit-message "Generate a commit message for my staged changes"

Interactive Mode

Run the skill and describe what you changed:

skillx run github:skillx-run/skillx/examples/skills/commit-message "Generate a commit message for my staged changes"

The agent reads your staged diff and produces a commit message.

Piped Input with —stdin

The most powerful usage pipes a diff directly into the skill:

git diff --staged | skillx run github:skillx-run/skillx/examples/skills/commit-message --stdin

This sends the staged diff as input to the agent. The skill’s instructions tell the agent to analyze the diff and generate a conventional commit message.

Print Mode (Non-Interactive)

Use --print to output the skill content without launching an interactive session. This is useful for scripting:

git diff --staged | skillx run github:skillx-run/skillx/examples/skills/commit-message --stdin --print

In --print mode, skillx outputs the skill instructions to stdout and exits immediately — no agent session is created, no cleanup is needed.

Workflow Examples

Quick Commit Message

A one-liner to generate and review a commit message:

git diff --staged | skillx run github:skillx-run/skillx/examples/skills/commit-message --stdin

The agent outputs something like:

feat(scanner): add SARIF 2.1.0 output format

Add structured SARIF output to the scan report formatter, enabling
integration with GitHub Code Scanning and other SARIF-compatible
tools.

Review Before Committing

Generate the message, review it, then commit:

# Stage your changes
git add -p

# Generate the commit message
skillx run github:skillx-run/skillx/examples/skills/commit-message "Generate a commit message for my staged changes"

# Copy the suggested message and commit
git commit -m "feat(scanner): add SARIF 2.1.0 output format"

Diff of Recent Commits

Generate a message for squashing recent commits:

git diff HEAD~3 | skillx run github:skillx-run/skillx/examples/skills/commit-message --stdin

PR Description

The skill also works for pull request descriptions by providing a broader diff:

git diff main...HEAD | skillx run github:skillx-run/skillx/examples/skills/commit-message --stdin

The Conventional Commits Format

The skill enforces the Conventional Commits specification:

<type>(<scope>): <subject>

<body>

Types

Type	When to Use
`feat`	New feature
`fix`	Bug fix
`refactor`	Code change that neither fixes a bug nor adds a feature
`docs`	Documentation changes
`test`	Adding or updating tests
`chore`	Build process, CI, dependencies
`perf`	Performance improvement
`style`	Formatting, whitespace (no logic change)

Rules

Subject line — Max 72 characters, imperative mood (“add” not “added”), no trailing period
Body — Explains the “why” not the “what” (the diff shows the what)
Multiple changes — If the diff contains multiple logical changes, the skill suggests splitting into separate commits

Team Configuration

Add the commit-message skill to your project’s skillx.toml for consistent commit messages across the team:

[skills]
commit-message = "github:skillx-run/skillx/examples/skills/commit-message"

Then any team member can run:

git diff --staged | skillx run --stdin

The skillx run command (with no source argument) reads from skillx.toml and uses the configured skills.

Why this example exists

This example exists to show how a skill can read staged changes, infer intent, and emit a commit message that fits non-interactive shell workflows and Git habits.

Next Steps

If you want a companion pattern for review workflows, open Code Review. If you want to build your own command-line skill around a different Git task, use Writing Skills. If you are comparing this with upstream workflows, check Famous Skills.