# Summarize Diff

> Summarize a git diff into a reviewer-facing changelog grouped by subsystem. Use when preparing a change review.

- Skill: `stbenjam/summarize-diff` (Agent Skill)
- Install (CLI): `npx skillmds@latest add stbenjam/summarize-diff`
- Raw SKILL.md: https://api.skillmd.com/api/skills/stbenjam/summarize-diff/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Research & Search
- Author: stbenjam (https://skillmd.com/u/stbenjam)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/stbenjam/summarize-diff

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# Summarize Diff

Use this skill when the user asks what changed in a branch or a pull request
and wants a summary they can paste into a review.

## Steps

1. Run `git diff --stat` against the base branch to see which files changed.
2. Group the changed files by subsystem, using the top-level directory name.
3. For each group, read the diff and write one sentence describing the change.
4. Emit a markdown list with one bullet per group.

Stop once the summary is written. Do not commit, push, or open a pull request.