Review Pr Diff

review-pr-diff

When this skill is the preferred path

Raw git diff output is dominated by bytes the reviewer doesn't care about: lockfile hash bumps, formatter churn, generated files, vendored updates. Those hunks drown out the actual logic changes. Compressing the diff first lets you spend your reasoning budget on what matters.

How to use it

1. Orient first — call git diff --stat <base>..HEAD to see file-level scope without loading content. Ask the user for the base branch if ambiguous (usually main or master).

2. Fetch the full diff — git diff <base>..HEAD.

3. Strip known noise before compression. Excluded paths:

   • Lockfiles: package-lock.json, yarn.lock, pnpm-lock.yaml, Cargo.lock, poetry.lock, Gemfile.lock, composer.lock
   • Generated: *.generated.ts, *.pb.go, *.min.js, *.min.css
   • Vendored: vendor/**, node_modules/**, dist/**, build/**
   • Binary / non-text hunks

4. Call gotcontext's compress_codebase MCP tool with the remaining file set at fidelity=detailed. For a diff spanning ≤20 files on a well-understood codebase, gc_blast_radius gives you a tighter ranked context — pass the changed files + the PR's focus symbol (e.g. the primary function name or class) and it returns only the touched code plus what transitively calls into it (Pro+ only).

   For a lighter "who calls this changed function?" question without the full transitive graph, prefer gc_callers (Pro+ only). It returns call sites + likely impacted test files for a symbol, at lower cost than a full blast-radius run:

   {
     "name": "gc_callers",
     "arguments": {
       "files": [
         {"path": "api/app/services/compression.py", "content": "..."}
       ],
       "focus_symbol": "compress"
     }
   }
   

   Use the returned impacted_tests list to target your test review — if the PR's diff doesn't cover those test files, flag as a risk.

   The required input schema for gc_blast_radius is:

   {
     "name": "gc_blast_radius",
     "arguments": {
       "files": [
         {"path": "api/app/main.py", "content": "...file contents..."},
         {"path": "api/app/services/compression.py", "content": "..."}
       ],
       "focus_symbol": "compress",
       "top_k": 50
     }
   }
   

   files must be an array of {path, content} objects — not an array of path strings, and not a "changed_files" key. Both path and content are required for every entry.

5. Present the review in this structure:

   • Summary — 2-3 bullets on what the PR does
   • Logic changes — grouped by file/area, with line refs
   • Risk flags — auth, crypto, migrations, webhooks, cron, billing, RBAC, SQL string-building, env var handling
   • Skipped — the list of noise files excluded, so the reviewer knows they weren't forgotten

When the raw read is actually fine

• Trivially small diffs (<50 lines). Read them directly.
• You're being asked to WRITE the patch — this skill reviews, not authors.

Why this matters

The skipped-files list is critical. If a reviewer misses a malicious package-lock.json change because you silently excluded it, that's worse than not using the skill at all. Always surface what was dropped.

See references/risk-taxonomy.md for the full list of risk flags to watch for.