diff-analysis
Diff Analysis
Concept of the skill
Use when analyzing git diff, reviewing a patch before commit, or explaining what a changeset does.
Domain Context
What is this skill? This skill provides disciplined diff analysis for AI agents: reading code changes as a structured before/after artifact, isolating semantic changes from formatting noise, tracing blast radius across files, and extracting review-ready findings from a patch. Covers unified diff anatomy, hunk-by-hunk interpretation, scope validation, hidden-risk scanning, and intent-vs-diff comparison. Use when analyzing git diff, reviewing a patch before commit, or explaining what a changeset actually does. Do NOT use for full code-review verdicts (use code-review), git workflow decisions (use version-control), or pixel/image comparison (use playwright-cli or visual diff tooling).
Key Files
| File | Purpose |
|---|---|
skills/diff-analysis/references/repo-diff-patterns.md |
Repo-grounded patch examples showing how diff classes map to real changes in this workspace. |
skills/diff-analysis/references/diff-reading-checklist.md |
Step-by-step checklist for reading hunks, isolating semantic deltas, and naming blast radius. |
Coverage
This skill covers reading and interpreting unified diffs and patches: the anatomy of diff --git output, hunk-by-hunk semantic extraction, file-level change classification (rename, mechanical rewrite, local logic edit, contract edit, test-only edit), separating signal from formatting noise, blast radius estimation for changed contracts and types, intent-vs-diff mismatch detection, and writing concise behavior-focused diff summaries. Does not cover full code review verdicts, git workflow/branching decisions, or visual/pixel comparison.