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name: implementing-code description: Write clean, efficient, maintainable code. Use when implementing features, writing functions, or creating new modules. Covers SOLID principles, error handling, and code organization. allowed-tools: Read, Write, Edit, Bash, Glob, Grep

Implementing Code

Workflows

• Security Check: Injection flaws, auth issues, sensitive data exposure
• Performance Check: N+1 queries, memory leaks, inefficient algorithms
• Readability Check: SOLID principles, naming conventions, comments
• Testing Check: Edge cases, error paths, happy paths

Feedback Loops

1. Implement feature or fix
2. Run local tests (unit/integration)
3. Run linter/formatter
4. If failure, fix and repeat

Reference Implementation

SOLID Compliant Class (TypeScript)

Copy// Abstraction (Interface Segregation)
interface ILogger {
  log(message: string): void;
}

interface IUserRepository {
  save(user: User): Promise<void>;
}

// Domain Entity
class User {
  constructor(public readonly id: string, public readonly email: string) {}
}

// Implementation (Single Responsibility)
class UserService {
  constructor(
    private readonly userRepository: IUserRepository,
    private readonly logger: ILogger
  ) {}

  public async registerUser(email: string): Promise<User> {
    if (!email.includes('@')) {
      throw new Error("Invalid email format");
    }

    const user = new User(crypto.randomUUID(), email);
    await this.userRepository.save(user);
    this.logger.log(`User registered: ${user.id}`);

    return user;
  }
}

Code Review Checklist

• No hardcoded secrets or credentials
• Input validation on all external data
• Proper error handling with meaningful messages
• No N+1 query patterns
• Functions follow single responsibility principle
• Dependencies injected, not instantiated inline
• Tests cover happy path and edge cases