git-diff-summarizer

id	git-diff-summarizer
name	Git Diff Summarizer
version	1.0.0
description	Parses a git diff or patch file and produces a structured summary of changes: files modified, lines added and removed per file, a plain-English description of what changed, and a suggested conventional commit message following the feat/fix/chore/refactor/docs prefix convention.
capability	{"type":"data-transform","inputs":["diff_text:string","context:string"],"outputs":["files_changed:list","lines_added:int","lines_removed:int","summary:string","commit_message:string"]}
graph	{"depends_on":[],"complements":["github-pr-reviewer","code-review-commenter"],"co_used_with":["semantic-version-bumper"]}
compatibility	{"claude_code":true,"gemini":true,"codex":true,"cursor":true,"mcp":true}
risk	safe

What this skill does

Reads a raw git diff or unified diff text and returns a structured breakdown of what changed. Identifies the affected files, counts added and removed lines per file, writes a human-readable English summary of the change intent, and suggests a conventional commit message (feat:, fix:, chore:, refactor:, docs:) based on the change type detected.

Inputs

• diff_text — raw output of git diff, git diff HEAD, or a .patch file content
• context — optional string describing the purpose of the change (improves commit message quality)

Outputs

• files_changed — list of {path, additions, deletions, change_type} objects
• lines_added — total lines added across all files
• lines_removed — total lines removed across all files
• summary — 2–3 sentence plain-English description of what the diff does
• commit_message — suggested conventional commit message, e.g. fix: correct token expiry check in auth middleware

Example

git diff HEAD | asf query "summarize this diff and suggest a commit message"

Output:

{
  "files_changed": [
    {"path": "src/auth.js", "additions": 4, "deletions": 2, "change_type": "modified"}
  ],
  "lines_added": 4,
  "lines_removed": 2,
  "summary": "Fixed token expiry comparison using strict inequality. Updated unit test to cover the edge case.",
  "commit_message": "fix: use strict inequality for token expiry check in auth middleware"
}