Review

Code Review

$ARGUMENTS

Reviews code changes for quality and issues.

Changed files context

• Changes: !git diff --stat main...HEAD 2>/dev/null || git diff --cached --stat 2>/dev/null || echo "no changes detected"

Signal Collection (never stop at the first red)

Collect every failing signal up front, then review the diff in full anyway:

Each failing signal becomes a blocker finding. None of them ends the run.

A review that aborts on the first red signal spends the whole cycle repeating what the tracker already displayed, while the finding that would have told the author something new never gets written. One invocation produces the most complete picture of the change that it can.

Automated Diff Analysis

Before starting manual review, run the diff analyzer script to get a structured risk assessment:

python3 ${CLAUDE_SKILL_DIR}/scripts/diff-analyzer.py [base_branch]
# Default base branch: main
# Example: python3 ${CLAUDE_SKILL_DIR}/scripts/diff-analyzer.py develop

The script outputs JSON with:

• files: each changed file with additions, deletions, category (security/test/config/migration/infra/docs/logic), and risk level
• risk_score: overall assessment (high/medium/low)
• hotspots: top 5 files by additions
• secrets_scan: potential secret leaks detected in added lines
• test_coverage_estimate: whether test files accompany logic changes (good/partial/none)
• parallel_review_recommended: boolean flag

If the script reports parallel_review_recommended: true, use the Parallel Review (Agent Teams) mode below.

Parallel Review (Agent Teams)

For significant PRs or large changesets, create a parallel review team:

Create an agent team to review [target]:
- Teammate 1 (security-auditor): "Review for security vulnerabilities, auth issues,
  injection risks, secret leaks. Report with severity ratings." Use Opus.
- Teammate 2 (performance-optimizer): "Check for N+1 queries, memory leaks,
  unnecessary allocations, caching opportunities. Report with impact ratings." Use Opus.
- Teammate 3 (test-engineer): "Validate test coverage, edge cases, mock quality,
  missing assertions. Report coverage gaps." Use Opus.
Each reviewer should report findings independently. Do NOT modify files.

After all reviewers complete:

1. Synthesize findings into unified Code Review Report
2. Prioritize by severity (blocker > major > minor > nit)
3. Issue verdict per the verdict rule below — not by impression

When to use: PRs with >5 files changed, cross-module changes, security-sensitive code. READ-ONLY: No teammate should modify files during review.

Sequential Review (Default)

1. Reads changed files
2. Analyzes for issues
3. Checks best practices
4. Reports findings

Review Scope

Review Checklist

Code Quality

• Clear naming
• Proper error handling
• No code duplication
• Appropriate abstractions

Security (OWASP Top 10)

• A01: Proper auth/authorization on all endpoints
• A02: No weak crypto, HTTPS for external comms
• A03: Input validation, parameterized queries, output encoding (XSS)
• A04: Threat model assumptions documented for new features
• A05: No debug mode, default credentials, or verbose errors in prod config
• A06: Dependencies checked for known CVEs
• A07: No hardcoded secrets, session management correct
• A08: Integrity checks on deserialized data, CI/CD pipeline safety
• A09: Security-relevant events logged (without PII)
• A10: External URL handling validates scheme/host (SSRF prevention)
• Cross-scope replay: can an identifier from one tenant/user/org be replayed in another?
• Fails closed wherever the path affects security, money, or data retention

API / Contract Changes

• Backward compatibility preserved (no silent breaking changes)
• API versioning updated if contract changed
• Schema validation on request/response
• Client validation uses the authoritative input contract, including operation groups/defaults, finite bounds, nested paths and documented Unicode units; read reference/input-validation.md from the security-patterns skill located through the current client's installed catalog
• Shared backend/client fixtures and generation drift checks cover changed rules; unsupported/server-only checks are explicit, and local refusals do not masquerade as HTTP responses
• Error responses follow project convention
• Statuses and messages distinguish input/state refusals from infrastructure failures; original causes remain available in authorized diagnostics
• Error filtering preserves machine codes, field paths, JSON object/list types, locale and recovery headers; background-job error fields are covered too
• Retry advice reflects known persisted/provider state and does not invite blind replay of an uncertain mutation
• Wire-level contracts checked, not just code signatures: HTTP routes, webhook payloads, event/queue schemas

Concurrency / Async

• Shared mutable state protected (locks, atomics, channels)
• No fire-and-forget promises without error handling
• Database transactions scoped correctly (no long-held locks)
• Race condition risk assessed for concurrent access paths

Migrations / Schema Changes

• Migration is reversible (has rollback path)
• No table locks on large tables during peak hours
• Data backfill handles NULL/missing values
• Indexes added for new query patterns

Performance

• No N+1 queries
• Appropriate caching
• No memory leaks
• Optimized loops

Frontend & UI Craft (Anti-Slop Gates)

• No gradient text headlines (background-clip: text) or saturated purple/blue hero washes
• No cliché 3-column card grids with icon-above-title tiles, card-in-card nesting, or side-stripe cards
• Interactive elements implement all 8 states (default, hover, focus-visible, active, disabled, loading, error, success)
• Input fields maintain constant 1px border-width across all states (zero layout shift) and reserve 2px transparent outline
• Mobile responsive: overflow-x: clip on html and body; no buttons/links wrapping to 2 lines; image grid tracks use minmax(0, 1fr)
• Typography: headings are roman (font-style: normal, no italic emphasis in headers); max 3 font families (2+1 rule)
• Content honesty: no invented metrics ("+47% conversion"), fake testimonials, or placeholder stock logos
• No fake re-drawn browser/OS chrome; no emoji used as load-bearing icons

Testing

• Tests for new code
• Edge cases covered
• Mocks appropriate

Severity & Verdict

Verdict rule — apply it mechanically, do not negotiate with yourself:

• any blocker → REQUEST_CHANGES
• any major without a documented waiver (who waived it, why, what the follow-up is) → REQUEST_CHANGES
• only minor / nit → APPROVE
• the change cannot be classified from the diff → NEEDS_DISCUSSION, and state what would resolve it

Severity describes impact, confidence describes certainty — they are independent axes. A finding with confidence < 6 is reported at the tier its evidence supports and is never promoted to blocker on suspicion alone.

Output Format

## Code Review Report

### Summary
- **Files Changed**: [count]
- **Lines Added**: [+count]
- **Lines Removed**: [-count]
- **Issues Found**: [count]
- **Overall Confidence**: [1-10] — how confident the reviewer is in the assessment

### Findings

#### Blocker
- **[file:line]**: [issue]
  - Severity: blocker | Confidence: [1-10]
  - Evidence: [specific code reference and reasoning]
  - Suggested fix: [code]

#### Major
- **[file:line]**: [issue]
  - Severity: major | Confidence: [1-10]
  - Evidence: [specific code reference and reasoning]
  - Suggested fix: [code]

#### Minor
- **[file:line]**: [issue]
  - Severity: minor | Confidence: [1-10]
  - Evidence: [line number + reasoning]

#### Nit
- **[file:line]**: [suggestion]
  - Severity: nit | Confidence: [1-10]

### Confidence Guide

| Score | Meaning |
|-------|---------|
| 9-10 | Certain — verified via code, tests, or documentation |
| 7-8 | High — strong evidence, minor assumptions |
| 5-6 | Medium — plausible issue, needs author confirmation |
| 3-4 | Low — speculative, based on patterns not proof |
| 1-2 | Guess — flag for discussion, don't block on this |

### Positive Notes
- [What's good about the code]

### Verdict
[APPROVE / REQUEST_CHANGES / NEEDS_DISCUSSION]

State which clause of the verdict rule produced it, e.g.
"REQUEST_CHANGES — 1 blocker (auth.ts:88)" or
"APPROVE — 2 minor, 1 nit, no blocker or major".
Waived majors must name the waiver and the follow-up.

Common Rationalizations

Self-Evaluation (LLM-as-Judge)

After completing the review, perform a self-evaluation pass:

Check for Blind Spots

1. Did I verify, or assume? — For each finding, confirm you read the actual code (not inferred from context)
2. Did I miss the inverse? — If you flagged X as a problem, did you check if NOT doing X is also a problem elsewhere?
3. Did I anchor on the first issue? — Review whether early findings biased you toward similar patterns, missing different issue classes
4. Did I check the unhappy path? — Error handling, edge cases, failure modes — not just the golden path
5. Did I flag uncertainty? — Findings with confidence < 6 should be clearly marked as "needs author input"

Calibrate Confidence

• If all findings are confidence 7+, you may be overconfident — re-examine the weakest finding
• If any finding lacks a file:line reference, downgrade it or remove it
• If you found zero issues, state what you specifically checked (not "looks good")

READ-ONLY

This skill only analyzes. It does NOT modify any files.

Related Skills

• Issues found? → /debug to trace root causes
• Missing tests? → /tdd to add test-first coverage
• Security findings? → /cve-scan for dependency vulnerabilities
• Architecture concerns? → /analyze for deeper code quality metrics