Mobile

Use when creating SwiftData custom schema migrations with VersionedSchema and SchemaMigrationPlan - property type changes, relationship preservation (one-to-many, many-to-many), the willMigrate/didMigrate limitation, two-stage migration patterns, and testing migrations on real devices

Use when app feels slow, memory grows, battery drains, or diagnosing ANY performance issue. Covers memory leaks, profiling, Instruments workflows, retain cycles, performance optimization.

Use when implementing BGTaskScheduler, debugging background tasks that never run, understanding why tasks terminate early, or testing background execution - systematic task lifecycle management with proper registration, expiration handling, and Swift 6 cancellation patterns

Use when implementing navigation patterns, choosing between NavigationStack and NavigationSplitView, handling deep links, adopting coordinator patterns, or requesting code review of navigation implementation - prevents navigation state corruption, deep link failures, and state restoration bugs for iOS 18+

Use when working with SwiftData - @Model definitions, @Query in SwiftUI, @Relationship macros, ModelContext patterns, CloudKit integration, iOS 26+ features, and Swift 6 concurrency with @MainActor — Apple's native persistence framework

Use when app drains battery, device gets hot, users report energy issues, or auditing power consumption - systematic Power Profiler diagnosis, subsystem identification (CPU/GPU/Network/Location/Display), anti-pattern fixes for iOS/iPadOS

Reference — Complete SwiftUI adaptive layout API guide covering ViewThatFits, AnyLayout, Layout protocol, onGeometryChange, GeometryReader, size classes, and iOS 26 window APIs

Use when writing ANY code with async, actors, threads, or seeing ANY concurrency error. Covers Swift 6 concurrency, @MainActor, Sendable, data races, async/await patterns, performance optimization.

Use when building, fixing, or improving ANY iOS UI including SwiftUI, UIKit, layout, navigation, animations, design guidelines. Covers view updates, layout bugs, navigation issues, performance, architecture, Apple design compliance.

Reference — SwiftUI stacks, grids, outlines, and scroll enhancements through iOS 26

Use when implementing iOS 26 SwiftUI features - covers Liquid Glass design system, performance improvements, @Animatable macro, 3D spatial layout, scene bridging, WebView/WebPage, AttributedString rich text editing, drag and drop enhancements, and visionOS integration for iOS 26+

Use when debugging schema migration crashes, concurrency thread-confinement errors, N+1 query performance, SwiftData to Core Data bridging, or testing migrations without data loss - systematic Core Data diagnostics with safety-first migration patterns

Use when needing thread-safe primitives for performance-critical code. Covers Mutex (iOS 18+), OSAllocatedUnfairLock (iOS 16+), Atomic types, when to use locks vs actors, deadlock prevention with Swift Concurrency.

Use when app runs at unexpected frame rate, stuck at 60fps on ProMotion, frame pacing issues, or configuring render loops. Covers MTKView, CADisplayLink, CAMetalDisplayLink, frame pacing, hitches, system caps.

Use when testing async code with Swift Testing. Covers confirmation for callbacks, @MainActor tests, async/await patterns, timeout control, XCTest migration, parallel test execution.

Use when profiling async/await performance, diagnosing actor contention, or investigating thread pool exhaustion. Covers Swift Concurrency Instruments template, task visualization, actor contention analysis, thread pool debugging.

Apple platform typography reference (San Francisco fonts, text styles, Dynamic Type, tracking, leading, internationalization) through iOS 26

Use when implementing SwiftUI animations, understanding VectorArithmetic, using @Animatable macro, zoom transitions, UIKit/AppKit animation bridging, choosing between spring and timing curve animations, or debugging animation behavior - comprehensive animation reference from iOS 13 through iOS 26

Use when SwiftData migrations crash, fail to preserve relationships, lose data, or work in simulator but fail on device - systematic diagnostics for schema version mismatches, relationship errors, and migration testing gaps

Use when integrating ANY iOS system feature - Siri, Shortcuts, Apple Intelligence, widgets, IAP, camera, photo library, photos picker, audio, haptics, localization, privacy. Covers App Intents, WidgetKit, StoreKit, AVFoundation, PHPicker, PhotosPicker, Core Haptics, App Shortcuts, Spotlight.