summarize-changes

name	summarize-changes
description	Analyzes git diff output and produces a human-readable summary of all changes, grouped by component or module. Use when preparing PR descriptions, commit messages, or change reviews.
argument-hint	optional: commit range or branch comparison

Summarize Changes

Analyzes the current git diff and produces a structured, human-readable summary of all changes grouped by component.

When to Use

• Preparing a PR description and need a "What changed" section
• Reviewing what was implemented before committing
• Asked to "summarize changes", "what changed", "describe the diff"

Procedure

1. Get the diff statistics:

   git diff --stat
   

   For comparing against a branch:

   git diff --stat main...HEAD
   

2. Get the full diff for analysis:

   git diff
   

   For committed changes not yet pushed:

   git diff origin/main...HEAD
   

3. Analyze and group changes by component/module:

   • Group files by their top-level directory or module
   • For each group, summarize what changed and why
   • Highlight new files vs. modified files vs. deleted files

4. Produce a structured summary:

   ## Changes Summary
   
   **Stats:** X files changed, Y insertions(+), Z deletions(-)
   
   ### <Component/Module 1>
   - `path/to/file.ts` — <what changed and why>
   - `path/to/other.ts` — <what changed and why>
   
   ### <Component/Module 2>
   - `path/to/file.py` — <what changed and why>
   
   ### New Files
   - `path/to/new.ts` — <purpose of this new file>
   
   ### Deleted Files
   - `path/to/old.ts` — <why removed>
   

5. For each file change, describe:

   • What was added/modified/removed
   • The intent behind the change (not just "added line 42")
   • Any behavioral impact

Important

• Describe changes at a semantic level ("added retry logic to API client"), not line level ("added lines 42-58")
• Highlight breaking changes prominently
• Note any changes to public APIs, interfaces, or contracts
• If a change touches tests, mention what scenario is being tested
• Keep descriptions concise — one line per file unless the change is complex