---

name: auth-builder description: Guide for adding authentication to web applications. This skill should be used when users want to implement login, signup, or access control.

Auth Builder

Add authentication to web applications.

When to Use

Use when a user asks to:

• Add login/signup
• Implement authentication
• Secure an application

How to Add Authentication

Step 1: Choose Method

• JWT tokens
• Session-based
• OAuth providers

Step 2: Create User Model

Copyconst userSchema = {
  email: String,
  password: String, // hashed
};

Step 3: Implement Signup

Hash password and store user.

Step 4: Implement Login

Verify credentials and issue token/session.

Step 5: Protect Routes

Add middleware to check authentication.

Copyconst authMiddleware = (req, res, next) => {
  const token = req.headers.authorization;
  if (!token) return res.status(401).send('Unauthorized');
  // verify token
  next();
};

Output

• User model
• Auth routes (signup, login, logout)
• Auth middleware