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understand-diff (Change Impact Analysis)

Cross-references a git diff or PR against your project's knowledge graph to report changed components, blast radius and risk.

Dev & CodingIntermediate★ 78,314⑂ 6,578AI score 7/10Last updated: Jul 30, 2026

What it does

This skill compares your current code changes (git diff) or a specified PR against the project's knowledge graph (.ua/knowledge-graph.json).

  • Locates graph nodes (file, function, class, config, document, endpoint...) for each changed path.
  • Follows 1-hop edges to list upstream callers/dependents and downstream dependencies.
  • Identifies which architectural layers are touched and flags cross-layer concerns.
  • Produces a risk assessment from node complexity, cross-layer edges and blast radius, plus review hints.
  • Writes diff-overlay.json so the dashboard can highlight changed vs. affected nodes.
  • Detects a stale graph by comparing the graph's recorded commit with HEAD (monorepo-aware pathspec included).

Who it's for

  • Reviewers handling PRs in large codebases
  • Developers who worry "what breaks if I touch this file?"
  • Teams on monorepos or layered architectures needing cross-layer impact checks
  • New joiners who need to size up the ripple effect of a change fast

Examples

  1. Pre-PR sanity check — run it on a feature branch; it uses git diff main...HEAD to summarize changed components, affected components and a risk grade.
  2. Refactor safety net — after editing a shared utility function, pull every upstream module that calls it to scope your test run.
  3. Visual review — after the analysis, run /understand-anything:understand-dashboard to view the diff overlay on the graph.

· · · Install guide · · ·

Install in the Claude app (no terminal)
  1. Download the ZIP with the button below.
  2. In Claude, open Settings → Capabilities and turn on 'Code execution and file creation'. (one time)
  3. Go to Customize → Skills → + → 'Upload a skill' and upload the ZIP.
↓ Download ZIP
Install in Claude Code

Let Claude do it — paste this into Claude Code

Install the skill I found on Claude Skill Mart.
Copy the understand-anything-plugin/skills/understand-diff folder from the GitHub repo Egonex-AI/Understand-Anything into my ~/.claude/skills/understand-diff/.
When it's done, tell me in one line what this skill can do.

Install with a command instead

git clone https://github.com/Egonex-AI/Understand-Anything.git /tmp/understand-anything && mkdir -p ~/.claude/skills && cp -r /tmp/understand-anything/understand-anything-plugin/skills/* ~/.claude/skills/

⚠ This is a third-party skill. Check the source repository before installing.

  1. Open a terminal and clone the repo: git clone https://github.com/Egonex-AI/Understand-Anything.git
  2. Create the skills folder if needed: mkdir -p ~/.claude/skills
  3. Copy the skills over: cp -r Understand-Anything/understand-anything-plugin/skills/* ~/.claude/skills/ (copy all of them — understand-diff relies on the graph built by the /understand skill)
  4. Launch Claude Code inside the project you want to analyze.
  5. Run /understand first to generate the .ua/knowledge-graph.json knowledge graph.
  6. Then invoke /understand-diff or simply ask "analyze the impact of my current changes".
  7. Optionally run /understand-anything:understand-dashboard to see the diff overlay visually.
View source on GitHub ↗License: MIT