Code Review Skill

Conduct a thorough code review for quality, security, and maintainability with severity-rated feedback.

When to Use

This skill activates when:

• User requests "review this code", "code review"
• Before merging a pull request
• After implementing a major feature
• User wants quality assessment

What It Does

GPT-5.4 Guidance Alignment

• Default to concise, evidence-dense progress and completion reporting unless the user or risk level requires more detail.
• Treat newer user task updates as local overrides for the active workflow branch while preserving earlier non-conflicting constraints.
• If correctness depends on additional inspection, retrieval, execution, or verification, keep using the relevant tools until the review is grounded.
• Continue through clear, low-risk, reversible next steps automatically; ask only when the next step is materially branching, destructive, or preference-dependent.

Delegates to the code-reviewer agent (THOROUGH tier) for deep analysis:

1. Identify Changes
   • Run git diff to find changed files
   • Determine scope of review (specific files or entire PR)
2. Review Categories
   • Security - Hardcoded secrets, injection risks, XSS, CSRF
   • Code Quality - Function size, complexity, nesting depth
   • Performance - Algorithm efficiency, N+1 queries, caching
   • Best Practices - Naming, documentation, error handling
   • Maintainability - Duplication, coupling, testability
3. Severity Rating
   • CRITICAL - Security vulnerability (must fix before merge)
   • HIGH - Bug or major code smell (should fix before merge)
   • MEDIUM - Minor issue (fix when possible)
   • LOW - Style/suggestion (consider fixing)
4. Specific Recommendations
   • File:line locations for each issue
   • Concrete fix suggestions
   • Code examples where applicable

Agent Delegation

delegate(
  role="code-reviewer",
  tier="THOROUGH",
  prompt="CODE REVIEW TASK

Review code changes for quality, security, and maintainability.

Scope: [git diff or specific files]

Review Checklist:
- Security vulnerabilities (OWASP Top 10)
- Code quality (complexity, duplication)
- Performance issues (N+1, inefficient algorithms)
- Best practices (naming, documentation, error handling)
- Maintainability (coupling, testability)

Output: Code review report with:
- Files reviewed count
- Issues by severity (CRITICAL, HIGH, MEDIUM, LOW)
- Specific file:line locations
- Fix recommendations
- Approval recommendation (APPROVE / REQUEST CHANGES / COMMENT)"
)

External Model Consultation (Preferred)

The code-reviewer agent SHOULD consult Codex for cross-validation.

Protocol

1. Form your OWN review FIRST - Complete the review independently
2. Consult for validation - Cross-check findings with Codex
3. Critically evaluate - Never blindly adopt external findings
4. Graceful fallback - Never block if tools unavailable

When to Consult

• Security-sensitive code changes
• Complex architectural patterns
• Unfamiliar codebases or languages
• High-stakes production code

When to Skip

• Simple refactoring
• Well-understood patterns
• Time-critical reviews
• Small, isolated changes

Tool Usage

Before first MCP tool use, call ToolSearch("mcp") to discover deferred MCP tools. Use mcp__x__ask_codex with agent_role: "code-reviewer". If ToolSearch finds no MCP tools, fall back to the code-reviewer agent.

Note: Codex calls can take up to 1 hour. Consider the review timeline before consulting.

Output Format

CODE REVIEW REPORT
==================

Files Reviewed: 8
Total Issues: 15

CRITICAL (0)
-----------
(none)

HIGH (3)
--------
1. src/api/auth.ts:42
   Issue: User input not sanitized before SQL query
   Risk: SQL injection vulnerability
   Fix: Use parameterized queries or ORM

2. src/components/UserProfile.tsx:89
   Issue: Password displayed in plain text in logs
   Risk: Credential exposure
   Fix: Remove password from log statements

3. src/utils/validation.ts:15
   Issue: Email regex allows invalid formats
   Risk: Accepts malformed emails
   Fix: Use proven email validation library

MEDIUM (7)
----------
...

LOW (5)
-------
...

RECOMMENDATION: REQUEST CHANGES

Critical security issues must be addressed before merge.

Review Checklist

The code-reviewer agent checks:

Security

• No hardcoded secrets (API keys, passwords, tokens)
• All user inputs sanitized
• SQL/NoSQL injection prevention
• XSS prevention (escaped outputs)
• CSRF protection on state-changing operations
• Authentication/authorization properly enforced

Code Quality

• Functions < 50 lines (guideline)
• Cyclomatic complexity < 10
• No deeply nested code (> 4 levels)
• No duplicate logic (DRY principle)
• Clear, descriptive naming

Performance

• No N+1 query patterns
• Appropriate caching where applicable
• Efficient algorithms (avoid O(n²) when O(n) possible)
• No unnecessary re-renders (React/Vue)

Best Practices

• Error handling present and appropriate
• Logging at appropriate levels
• Documentation for public APIs
• Tests for critical paths
• No commented-out code

Approval Criteria

APPROVE - No CRITICAL or HIGH issues, minor improvements only REQUEST CHANGES - CRITICAL or HIGH issues present COMMENT - Only LOW/MEDIUM issues, no blocking concerns

Scenario Examples

Good: The user says continue after the workflow already has a clear next step. Continue the current branch of work instead of restarting or re-asking the same question.

Good: The user changes only the output shape or downstream delivery step (for example make a PR). Preserve earlier non-conflicting workflow constraints and apply the update locally.

Bad: The user says continue, and the workflow restarts discovery or stops before the missing verification/evidence is gathered.

Use with Other Skills

With Team:

/team "review recent auth changes and report findings"

Includes coordinated review execution across specialized agents.

With Ralph:

/ralph code-review then fix all issues

Review code, get feedback, fix until approved.

With Ultrawork:

/ultrawork review all files in src/

Parallel code review across multiple files.

Best Practices

• Review early - Catch issues before they compound
• Review often - Small, frequent reviews better than huge ones
• Address CRITICAL/HIGH first - Fix security and bugs immediately
• Consider context - Some "issues" may be intentional trade-offs
• Learn from reviews - Use feedback to improve coding practices