scrutinize-change

name	scrutinize-change
description	Review a plan, diff, PR, or completed change with outsider skepticism. Check code paths, verify behavior, look for edge cases and test gaps. Trigger on /scrutinize-change, or when asked to review/audit/sanity-check changes.
user-invocable	true
allowed-tools	Read, Grep, Glob, Bash

Scrutinize Change

Stand outside the change and verify it does what it claims, end-to-end.

Workflow

1. Intent

• State the goal in one sentence. If you cannot, say so and stop.
• Is there a simpler way? Consider: doing nothing, using existing code, smaller change that covers 90%, solving at a different layer.

2. Trace

• Walk the actual code path end-to-end — entry point, call sites, branches, state mutations, exit/return.
• Include unchanged code on either side of the diff. Bugs hide at seams.
• For plans: trace proposed flow against the existing system. Note assumptions that aren't true.

3. Verify

• Does the traced path actually produce the claimed behavior?
• What inputs/states would break it? Edge cases, concurrency, errors, retries, empty/null inputs, ordering.
• What does it silently change? Performance, error semantics, observability, contracts.
• Do tests actually exercise the traced path, or do they pass while skipping it via mocks?

4. Report

Order by severity (blocker → major → nit). For each finding:

• Finding — one sentence, specific, cite file:line.
• Why it matters — consequence.
• Evidence — trace step or input that exposes it.
• Suggested fix — concrete, minimal.

Close with one-line verdict: ship / fix-then-ship / rework / reject.

Rules

• No rubber-stamps. If you find nothing, say what you traced and checked.
• Cite specific paths, files, or lines. No vague claims.
• Distinguish "the PR says X" from "I traced X and confirmed/refuted it."
• One pass asking "is this necessary at all" is mandatory.
• No flattery, no hedging. State the finding.

Experience Log

This skill learns from experience. Mechanism:

• Read .claude/experience/scrutinize-change.md at skill start to benefit from past lessons.

• Write to .claude/experience/scrutinize-change.md after use if you learned something new.

• Format: YYYY-MM-DD: <lesson> — one line per entry.

• Evolve: If the same issue repeats 3+ times, update this SKILL.md itself.

This skill improves over time. After each use, append lessons learned.

Record format: YYYY-MM-DD: <lesson> Read this at skill start to apply past lessons.