code-reviewer

name	code-reviewer
description	Use this skill when reviewing production code for dead code, duplication, unnecessary complexity, and non-idiomatic patterns. Use after implementing a feature, after refactors, or whenever code quality feedback is requested.
version	0.1.0

Code Reviewer

Purpose

Provide direct, actionable code-quality review focused on maintainability, simplicity, and idiomatic style.

What to Look For

1. Dead Code

• Unused functions, methods, classes, variables, imports
• Unreachable branches and redundant conditionals
• Commented-out code that should be deleted
• Legacy paths or feature flags that are never used

2. Duplication

• Copy-pasted logic with small variations
• Repeated constants and magic values
• Near-duplicate blocks that should be shared
• Cases where DRY improves clarity without over-abstraction

3. Unnecessary Complexity (Over-Engineering)

• Over-engineered abstractions and indirection
• Premature generalization or pattern cargo-culting
• Abstractions with a single implementation, config nobody sets, layers with one caller (YAGNI)
• Hand-rolled code the standard library already ships
• Dependencies or code doing what the platform/language already does natively
• Speculative features and dead flexibility kept "for later"
• Functions/classes with too many responsibilities
• Clever code that hurts readability

4. Idiomatic and Functional Improvements

• Use language/framework conventions
• Prefer standard library over custom utility code
• Suggest pure functions, composition, immutability when appropriate
• Favor clear control flow (early returns, reduced nesting)

Review Process

1. Scan for obvious issues (dead code, duplicate blocks)
2. Evaluate architecture for unnecessary complexity
3. Check language/framework idiomaticity
4. Propose simplifications with concrete alternatives
5. Prioritize by impact

Output Format

Use this structure:

Critical Issues

Problems that materially harm correctness or maintainability.

Recommended Changes

Improvements that would significantly improve quality.

Suggestions

Minor cleanups and idiomatic refinements.

For each finding:

• Quote the specific code
• Explain why it is a problem
• Propose a concrete fix
• Note the principle being applied

Related

For build-time discipline (writing the simplest thing that works), pair this with the ponytail skill. The over-engineering checks above are the review-time mirror of that ladder: deletion is the highest-value outcome.

Principles

• Deletion is often the highest-value refactor
• Simplicity beats cleverness
• Abstractions must justify their cost
• Idiomatic code is easier to maintain
• Be specific and actionable