/code-guardian:review

Perform a thorough code review of the current uncommitted changes or a specified file/directory.

Process

1. Gather the changes to review:

   • Run git diff for unstaged changes and git diff --cached for staged changes
   • If a specific file or directory is provided as an argument, focus the review there
   • If no changes exist, review the most recent commit with git diff HEAD~1

2. Analyze each changed file across these dimensions:

Correctness

• Logic errors, off-by-one mistakes, incorrect boolean conditions
• Unhandled null/undefined values and missing error boundaries
• Race conditions in async code, missing awaits, unhandled promise rejections
• Incorrect type assertions or unsafe casts

Security

• User input flowing to SQL queries, shell commands, or file paths without sanitization
• Hardcoded credentials, API keys, tokens, or connection strings
• Missing authentication or authorization checks on new endpoints
• Unsafe deserialization of external data

Performance

• N+1 query patterns in database access
• Unnecessary re-renders in React components (missing memoization, unstable references)
• Unbounded data fetching without pagination or limits
• Synchronous blocking operations on hot paths
• Memory leaks from unclosed resources, event listeners, or subscriptions

Design

• Single Responsibility violations: functions or classes doing too many things
• Tight coupling between modules that should be independent
• Missing abstractions where patterns repeat three or more times
• Public API surface area: are new exports intentional and well-designed?

Readability

• Variable and function names that obscure intent
• Deeply nested conditionals that should be flattened or extracted
• Magic numbers or strings that should be named constants
• Missing or misleading type annotations

3. Classify each finding by severity:

   • CRITICAL - Will cause bugs, data loss, or security vulnerabilities in production
   • WARNING - Likely to cause issues under certain conditions or during maintenance
   • SUGGESTION - Improvement opportunity that is not urgent

4. For each finding, provide:

   • The file path and line range
   • A clear description of the issue
   • A concrete fix or code suggestion

Output Format

Present findings grouped by severity, then by file. Lead with critical issues. Skip categories that have no findings. End with a brief summary of overall quality.

Rules

• Be specific and actionable, not vague ("this could be improved")
• Do not flag style preferences unless they impact readability significantly
• Acknowledge well-written code briefly at the end
• Limit total findings to the 15 most impactful to avoid noise
• If the diff is very large, prioritize new code over modified code