Object-Oriented Design Skill

This skill defines Core Engineering: Object-Oriented Programming (OOP), SOLID, clean-code principles, and relationship types with concrete examples so an AI agent or developer can apply them consistently.

1. Four Pillars of OOP

1.1 Abstraction

What it is: Focus on what an object does, not how. Hide complex details and expose only essential behavior.

How it looks: Public methods define the contract; internals are private or hidden.

// Abstraction: caller uses start() and stop() without knowing engine details
class Car {
  private engine: Engine;