AI Code Review Automation with Claude Code: 2025 Complete Guide

By Daniel Ávila and Claude Code Templates contributors. Original article.

What is the Code Reviewer Agent?

The Code Reviewer Agent is a specialized Claude Code agent focused on automated code quality and security analysis. It provides expert code reviews, detects security vulnerabilities, enforces best practices, and delivers actionable feedback to improve your codebase quality and maintainability.

Key Capabilities

• Automated Code Reviews (analyzes git diff for recent changes)
• Security Vulnerability Detection (exposed secrets, API keys, input validation)
• Code Quality Analysis (readability, naming conventions, duplication)
• Best Practices Enforcement (error handling, test coverage, performance)
• Prioritized Feedback (critical issues, warnings, suggestions)
• Actionable Recommendations (specific examples of how to fix issues)

Installation

Install the Code Reviewer Agent using the Claude Code Templates CLI:

npx claude-code-templates@latest --agent development-tools/code-reviewer

Where is the agent installed?

The agent is saved in .claude/agents/code-reviewer.md in your project directory:

your-project/
├── .claude/
│   └── agents/
│       └── code-reviewer.md    # ← Agent installed here
├── src/
│   └── components/
├── package.json
└── README.md

How to Use the Agent

Start Claude Code and explicitly request the agent in your prompt:

# Start Claude Code
claude

# Then write your prompt requesting the agent
> Use the code-reviewer agent to review my recent changes for security issues and code quality

The agent will automatically:

• Run git diff to see recent changes
• Focus review on modified files
• Provide feedback organized by priority (critical, warnings, suggestions)
• Include specific examples of how to fix identified issues

Usage Examples

Example 1: Security Audit Before Commit

claude

> Use the code-reviewer agent to check for security vulnerabilities in my code before I commit. Focus on exposed secrets, API keys, and input validation

Result: Comprehensive security review identifying exposed credentials, missing input validation, and SQL injection risks with specific fixes for each issue.

Example 2: Code Quality Review

claude

> Use the code-reviewer agent to review this pull request for code quality. Check for duplicated code, naming conventions, and error handling

Result: Detailed quality analysis highlighting code duplication, suggesting better variable names, and identifying missing error handling with refactoring examples.

Example 3: Performance and Best Practices

claude

> Use the code-reviewer agent to analyze performance issues and verify we're following best practices for this Node.js API

Result: Performance analysis identifying N+1 queries, missing database indexes, and inefficient loops with optimization recommendations and code examples.

Review Checklist

The Code Reviewer Agent evaluates code against this comprehensive checklist:

• ✓ Code is simple and readable
• ✓ Functions and variables are well-named
• ✓ No duplicated code
• ✓ Proper error handling implemented
• ✓ No exposed secrets or API keys
• ✓ Input validation present
• ✓ Good test coverage
• ✓ Performance considerations addressed

Official Documentation

For more information about agents in Claude Code, see the official sub-agents documentation.

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