Swift MVVM Skill

Help the agent produce better MVVM code for Swift projects.

Core stance

• Keep the ViewModel UI-framework agnostic. ViewModels should not import SwiftUI, UIKit, or AppKit.
• The ViewModel should be mostly (1) state, (2) intent methods, and (3) dependency coordination.
• Push work into smaller, testable units (pure structs/functions, use cases, controllers, repositories, mappers, formatters).
• Use dependency injection with protocols so everything is mockable.
• Extensions are encouraged for organization (especially protocol conformances).

When to use

Use this skill when the user asks to:

• Add or refactor features in SwiftUI/UIKit/AppKit and keep architecture clean.
• Create or improve a ViewModel (state, intents, effects) and move logic out of Views/ViewControllers.
• Fix state-management issues (wrong wrappers, threading warnings, unstable bindings).
• Improve testability (protocol-based dependencies, mocks/fakes, deterministic state updates).
• Reduce a “massive ViewModel” by splitting concerns.