AI Code Fixing Guides

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Professional documentation and insights

AI Code Fixing Guides

Learn how to identify, fix, and prevent common issues in AI-generated code. Transform ChatGPT prototypes into production-ready applications.


Why AI Code Needs Fixing

AI tools like ChatGPT, GitHub Copilot, and Claude are incredible for rapid prototyping. But they often generate code with:

  • Security vulnerabilities (hardcoded secrets, SQL injection risks)
  • Poor architecture (no separation of concerns, tight coupling)
  • Missing error handling (assumes happy paths only)
  • No testing strategy (works once, breaks later)
  • Performance issues (N+1 queries, memory leaks)

This guide helps you spot and fix these issues before they reach production.


Common AI Code Problems

1. Security Issues

Problem: AI often generates code with security flaws because it prioritizes “making it work” over “making it secure.”

Common Examples:

  • Hardcoded API keys and passwords
  • Missing input validation
  • SQL injection vulnerabilities
  • Exposed sensitive data in logs
  • CORS misconfiguration

How to Fix:

//  Bad (AI-generated)
const apiKey = "sk-1234567890abcdef";
const query = `SELECT * FROM users WHERE id = ${req.params.id}`;

//  Good (Production-ready)
const apiKey = process.env.API_KEY;
const query = `SELECT * FROM users WHERE id = ?`;
db.query(query, [req.params.id]);

Action Items:

  • Move all secrets to environment variables
  • Use parameterized queries or ORMs
  • Implement input validation and sanitization
  • Add authentication and authorization checks
  • Enable security headers (CORS, CSP, HSTS)

2. Error Handling

Problem: AI assumes everything works perfectly. Real applications need robust error handling.

Common Examples:

  • No try-catch blocks
  • Crashes on network failures
  • Silent failures
  • Poor error messages for users

How to Fix:

//  Bad (AI-generated)
async function fetchUser(id) {
  const response = await fetch(`/api/users/${id}`);
  return response.json();
}

//  Good (Production-ready)
async function fetchUser(id) {
  try {
    const response = await fetch(`/api/users/${id}`);

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }

    return await response.json();
  } catch (error) {
    console.error("Failed to fetch user:", error);
    throw new Error("Unable to load user data. Please try again.");
  }
}

Action Items:

  • Wrap async operations in try-catch
  • Validate API responses before processing
  • Log errors for debugging
  • Show user-friendly error messages
  • Implement retry logic for transient failures

3. Performance Issues

Problem: AI writes code that “works” but doesn’t scale.

Common Examples:

  • N+1 database queries
  • Loading unnecessary data
  • No caching strategy
  • Synchronous operations blocking the main thread
  • Memory leaks from unclosed connections

How to Fix:

//  Bad (AI-generated) - N+1 Query Problem
async function getUsersWithPosts() {
  const users = await db.query("SELECT * FROM users");
  for (let user of users) {
    user.posts = await db.query("SELECT * FROM posts WHERE user_id = ?", [
      user.id,
    ]);
  }
  return users;
}

//  Good (Production-ready) - Single Query with JOIN
async function getUsersWithPosts() {
  const query = `
    SELECT u.*, p.id as post_id, p.title, p.content
    FROM users u
    LEFT JOIN posts p ON u.id = p.user_id
  `;
  const rows = await db.query(query);
  // Transform flat results into nested structure
  return transformToNestedStructure(rows);
}

Action Items:

  • Use database joins instead of multiple queries
  • Implement pagination for large datasets
  • Add caching for frequently accessed data
  • Use lazy loading for heavy resources
  • Profile and optimize bottlenecks

4. Code Organization

Problem: AI generates everything in one file with no structure.

Common Examples:

  • 1000+ line files
  • Mixed concerns (UI, business logic, database)
  • No separation of routes, controllers, models
  • Duplicate code everywhere

How to Fix:

//  Bad Structure
app.js (2000 lines - everything in one file)

//  Good Structure
/src
  /routes
    user.routes.js
    auth.routes.js
  /controllers
    user.controller.js
    auth.controller.js
  /models
    user.model.js
  /middleware
    auth.middleware.js
    validation.middleware.js
  /services
    email.service.js
  /utils
    logger.js
  app.js

Action Items:

  • Separate concerns (MVC, Clean Architecture)
  • Create reusable utilities
  • Use dependency injection
  • Implement a clear folder structure
  • Extract business logic from routes

5. Missing Tests

Problem: AI doesn’t write tests. Your code works once, then breaks silently.

Common Examples:

  • No unit tests
  • No integration tests
  • No test data or fixtures
  • Untested edge cases

How to Fix:

//  Add Unit Tests
describe("User Service", () => {
  it("should create a new user with valid data", async () => {
    const userData = { name: "John", email: "[email protected]" };
    const user = await createUser(userData);

    expect(user).toBeDefined();
    expect(user.email).toBe("[email protected]");
  });

  it("should throw error for invalid email", async () => {
    const userData = { name: "John", email: "invalid-email" };

    await expect(createUser(userData)).rejects.toThrow("Invalid email");
  });
});

Action Items:

  • Write unit tests for business logic
  • Add integration tests for API endpoints
  • Test error cases and edge conditions
  • Set up CI/CD to run tests automatically
  • Aim for 70%+ code coverage

6. Environment Configuration

Problem: AI hardcodes values that should be configurable.

Common Examples:

  • Hardcoded database URLs
  • Fixed port numbers
  • Environment-specific logic mixed in code
  • No .env file support

How to Fix:

//  Bad (AI-generated)
const app = express();
app.listen(3000);
mongoose.connect("mongodb://localhost:27017/myapp");

//  Good (Production-ready)
require("dotenv").config();

const PORT = process.env.PORT || 3000;
const MONGO_URI = process.env.MONGO_URI || "mongodb://localhost:27017/myapp";

app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});

mongoose.connect(MONGO_URI, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

Action Items:

  • Use environment variables for all config
  • Create .env.example file
  • Document required environment variables
  • Use different configs for dev/staging/production
  • Never commit secrets to git

7. Database Issues

Problem: AI generates inefficient database schemas and queries.

Common Examples:

  • No indexes on frequently queried fields
  • Missing foreign key constraints
  • No data validation at database level
  • Poor normalization

How to Fix:

--  Bad (AI-generated)
CREATE TABLE users (
  id INT,
  email VARCHAR(255),
  name VARCHAR(255)
);

--  Good (Production-ready)
CREATE TABLE users (
  id INT PRIMARY KEY AUTO_INCREMENT,
  email VARCHAR(255) NOT NULL UNIQUE,
  name VARCHAR(255) NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  INDEX idx_email (email)
);

Action Items:

  • Add proper constraints (NOT NULL, UNIQUE, FOREIGN KEY)
  • Create indexes on searched/filtered columns
  • Use transactions for multi-step operations
  • Implement soft deletes when needed
  • Use migrations for schema changes

8. API Design

Problem: AI creates inconsistent, poorly documented APIs.

Common Examples:

  • Inconsistent response formats
  • No API versioning
  • Missing status codes
  • No rate limiting

How to Fix:

//  Bad (AI-generated)
app.get("/user/:id", async (req, res) => {
  const user = await getUser(req.params.id);
  res.send(user);
});

//  Good (Production-ready)
app.get("/api/v1/users/:id", async (req, res) => {
  try {
    const user = await getUser(req.params.id);

    if (!user) {
      return res.status(404).json({
        success: false,
        error: "User not found",
      });
    }

    res.status(200).json({
      success: true,
      data: user,
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: "Internal server error",
    });
  }
});

Action Items:

  • Use consistent response formats
  • Return appropriate HTTP status codes
  • Implement API versioning
  • Add rate limiting and throttling
  • Document endpoints with OpenAPI/Swagger

Quick Fixes Checklist

Use this checklist to audit AI-generated code:

Security:

  • No hardcoded secrets (use environment variables)
  • Input validation on all user inputs
  • Parameterized queries (no SQL injection)
  • Authentication and authorization implemented
  • Security headers configured

Error Handling:

  • Try-catch blocks around async operations
  • Validation of external API responses
  • User-friendly error messages
  • Proper error logging
  • Graceful degradation

Performance:

  • No N+1 query problems
  • Database indexes on queried fields
  • Caching for expensive operations
  • Pagination for large datasets
  • Connection pooling configured

Code Quality:

  • Proper folder structure
  • Separation of concerns
  • No code duplication
  • Meaningful variable names
  • Comments for complex logic

Testing:

  • Unit tests for business logic
  • Integration tests for APIs
  • Edge cases covered
  • CI/CD pipeline configured

Configuration:

  • Environment variables for config
  • .env.example file created
  • Different configs per environment
  • No secrets in version control

When to Get Professional Help

Some issues require experienced developers:

  • Complex architectural decisions
  • Large-scale refactoring
  • Performance optimization under load
  • Security audits for sensitive data
  • Migration to microservices
  • Setting up proper CI/CD pipelines

If you’re overwhelmed or need production-ready code fast, get in touch — we specialize in fixing AI-generated code.


Resources

Tools We Recommend:

  • ESLint/Prettier - Code quality and formatting
  • SonarQube - Static code analysis
  • OWASP ZAP - Security scanning
  • Jest/Mocha - Testing frameworks
  • Docker - Containerization
  • GitHub Actions - CI/CD

Further Reading:


Need Help?

Have AI-generated code that needs fixing? We specialize in transforming ChatGPT prototypes into production-ready applications.

Contact Us to discuss your project.


Last updated: December 14, 2025