# Git Diff

> Returns unified diff output for a git repository, with optional ref and path filters.

- Skill: `firma-ai/git-diff` (Agent Skill)
- Install (CLI): `npx skillmds@latest add firma-ai/git-diff`
- Raw SKILL.md: https://api.skillmd.com/api/skills/firma-ai/git-diff/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: MIT-0
- Author: Firma-AI (https://skillmd.com/u/firma-ai)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/firma-ai/git-diff

---


# /git_diff — View Diff Output

You are the **git_diff** tool for Clawthority. You return unified diff output from a git repository by running `git diff`.

## What You Do

You query the git diff and return a unified diff string. When no `ref` is provided, you show unstaged changes (working tree vs index). When a `ref` is provided, you compare the working tree against that commit. The output is filtered by `path` when specified.

## When to Trigger

Invoke this tool when the user or agent wants to:

- View unstaged changes in the working tree (`show me what I changed`)
- Compare the current state against a specific commit (`what changed since abc1234?`)
- Inspect changes to a specific file (`show me the diff for src/index.ts`)
- Review changes before staging or committing

## Parameters

| Name   | Type     | Required | Description                                                                 |
|--------|----------|----------|-----------------------------------------------------------------------------|
| `ref`  | `string` | No       | Commit ref to diff against. Omit to diff working tree against the index.    |
| `path` | `string` | No       | Restrict diff output to this file path.                                     |

## Result

| Name   | Type     | Description                                                        |
|--------|----------|--------------------------------------------------------------------|
| `diff` | `string` | Unified diff output. Empty string when there are no differences.   |

## Example Usage

```json
{
  "tool": "git_diff",
  "params": {}
}
```

```json
{
  "tool": "git_diff",
  "params": {
    "ref": "HEAD~1"
  }
}
```

```json
{
  "tool": "git_diff",
  "params": {
    "ref": "abc1234",
    "path": "src/index.ts"
  }
}
```

## Error Handling

| Error Code  | Cause                                                               |
|-------------|---------------------------------------------------------------------|
| `git-error` | `git diff` exited with a non-zero status (e.g. not a git repo, invalid ref). |

## Out of Scope

- Binary file diffs
- External diff tools
- Staged changes (`git diff --cached`)
- Diff statistics only (`git diff --stat`)

## Action Class

This tool is classified as `vcs.read` — a low-risk read-only operation that does not modify the git index or working tree. It is not subject to HITL gating.