Use when writing or reviewing Objective-C — including adding features to existing ObjC pages — debugging retain cycles, reasoning about blocks or ARC, using runtime features, or bridging Objective-C with Swift.
Use when organizing or standardizing an Apple app repository, choosing project structure or architecture, deciding package strategy, evaluating third-party libraries, or determining page communication patterns — for UIKit-first, Swift/Objective-C mixed, or SwiftUI apps. Applies to new pages and modifications to existing pages alike.
Use when writing, reviewing, or migrating Swift application code across Swift 4.2 through 6.3 — including adding features to existing Swift pages. Especially for concurrency, Combine, Codable, observation, Swift Testing, interoperability, and version-sensitive language decisions.
Use when building, reviewing, or modernizing UIKit screens for iOS 13 through iOS 26 — including adding new features to existing pages. Especially for collection views, diffable data sources, compositional layout, keyboard-safe layout, scenes, and modern presentation patterns.