Claude Code is Anthropic's AI coding assistant, but many developers only use about 30% of what it can do. This article walks you through 10 hidden commands that the official docs never highlight, each of which can double your development speed.

Prerequisites

• Claude Code installed (VS Code extension or standalone client)
• A code project you can test against
• Basic command-line experience

1. /review - Smart Code Review

This command performs a deep review of the current file or selected code — it doesn't just check for syntax errors, it also flags potential performance issues, security vulnerabilities, and best-practice violations.

# Type this in Claude Code
/review

What it actually catches:

• Unhandled exceptions
• Possible memory leaks
• Suggestions for more efficient algorithm implementations

Pro tip: Run /review once before submitting a PR and you'll avoid 90% of the back-and-forth in code review.

2. /test - Auto-Generate Test Cases

Claude Code analyzes your function logic and automatically generates boundary-condition tests, exception-handling tests, and performance tests.

# Select a function, then type
/test

It generates tests like this:

describe('calculateDiscount', () => {
  it('should handle zero price', () => {
    expect(calculateDiscount(0, 0.1)).toBe(0);
  });

  it('should throw error for negative discount', () => {
    expect(() => calculateDiscount(100, -0.1)).toThrow();
  });
});

3. /refactor - Smart Refactoring Suggestions

Unlike simple code formatting, /refactor analyzes code structure and proposes architecture-level improvements.

/refactor extract-component
/refactor simplify-logic
/refactor improve-naming

Word of caution: Refactoring suggestions won't all fit your project — understand the reasoning before you apply them.

4. /explain - Deep Code Explanation

Stuck on code you can't decipher? /explain breaks down what it does in plain language, including the algorithm behind it and the design intent.

# Select a complex code block
/explain --verbose

When to use it:

• Taking over someone else's legacy code
• Learning how an open-source project implements something
• Understanding complex algorithm logic

5. /fix - One-Click Error Fixing

When your code has compile errors or runtime exceptions, /fix automatically analyzes the error messages and proposes a fix.

/fix

It fixes more than syntax errors — it also handles:

• Type mismatches
• Missing dependency imports
• API call errors

6. /optimize - Performance Optimization

This command analyzes your code's time and space complexity and proposes optimizations.

/optimize --focus=speed
/optimize --focus=memory

Real example: We used it to optimize a data-processing function from O(n²) down to O(n log n), cutting the time to process 100,000 records from 5 seconds to 0.3 seconds.

7. /docs - Automatic Documentation

Generates JSDoc, docstrings, or README documentation automatically from your code logic.

/docs --format=jsdoc
/docs --format=markdown

The generated docs include:

• Function parameter descriptions
• Return types
• Usage examples
• Caveats to watch for

8. /security - Security Vulnerability Scanning

Dedicated to security checks, and goes deeper than /review.

/security

Problems it can find:

• SQL injection risks
• XSS vulnerabilities
• Sensitive data exposure
• Insecure dependency versions

9. /migrate - Code Migration Assistant

Helps you migrate from one framework or language to another.

/migrate from=react-class to=react-hooks
/migrate from=javascript to=typescript

Pro tip: Always run the full test suite after a migration — AI can't guarantee 100% correctness.

10. /context - Project Context Analysis

Has Claude Code build an understanding of your entire project structure, so its answers get more accurate from then on.

/context analyze

This command will:

• Scan the project's file structure
• Identify the tech stack in use
• Understand the dependency relationships between code

Usage tip: Run it once when starting a new project or switching between projects.

Combining Them in Practice

These commands work even better in combination:

# A complete code-quality check pipeline
/context analyze
/review
/security
/test
/docs

FAQ

Q: Do these commands modify my code? A: Not by default. They only offer suggestions; changes are applied only after you confirm manually.

Q: Which programming languages are supported? A: All the mainstream ones (JavaScript, Python, Java, Go, Rust, etc.), though Python and JavaScript get the best support.

Q: What if a command fails? A: Check that you've selected the right scope of code, or try /help to see the command's correct usage.

Wrap-Up

These 10 hidden commands cover every stage of the development workflow:

• Before writing code: /context to understand the project
• While writing code: /explain to learn, /refactor to improve
• After writing code: /review, /security, and /test to guarantee quality
• Maintenance: /fix, /optimize, and /migrate for continuous improvement

Master these commands and you turn Claude Code from a "chat tool" into a true "coding partner."

Related resources:

• Claude Code official documentation
• Command cheatsheet