Use when writing, reviewing, or refactoring SwiftUI code for iOS or macOS, including state management and `@Observable` data flow, view composition and invalidation/performance, lists and `ForEach` identity, environment usage, localization, animations, Liquid Glass adoption, migrating soft-deprecated APIs, or Instruments `.trace` capture/analysis for hangs, hitches, CPU hotspots, or excessive view updates.
2026-07-19