Skills by charleswiltgen

This skill documents building apps with SwiftData, including `@Model` definitions, `@Query`, relationships, background import patterns, and CloudKit sync. It includes explicit CloudKit configuration that enables network sync to `iCloud.com.example.MusicApp`.

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+

This skill provides environment-first diagnostics and repair steps for Xcode projects, with concrete shell commands for cleaning Derived Data and managing simulators. It instructs executing local commands such as `rm -rf ~/Library/Developer/Xcode/DerivedData/*` and `killall -9 xcodebuild`, which modify or kill local resources.

Use when separating logic from SwiftUI views, choosing architecture patterns, refactoring view files, or asking 'where should this code go', 'how do I organize my SwiftUI app', 'MVVM vs TCA vs vanilla SwiftUI', 'how do I make SwiftUI testable' - comprehensive architecture patterns with refactoring workflows for iOS 26+

Use when implementing Liquid Glass effects, reviewing UI for Liquid Glass adoption, debugging visual artifacts, optimizing performance, or requesting expert review of Liquid Glass implementation - provides comprehensive design principles, API patterns, and troubleshooting guidance from WWDC 2025. Includes design review pressure handling and professional push-back frameworks

Use when layouts need to adapt to different screen sizes, iPad multitasking, or iOS 26 free-form windows — decision trees for ViewThatFits vs AnyLayout vs onGeometryChange, size class limitations, and anti-patterns preventing device-based layout mistakes

Use when writing ANY test, debugging flaky tests, making tests faster, or asking about Swift Testing vs XCTest. Covers unit tests, UI tests, fast tests without simulator, async testing, test architecture.

Use when implementing SwiftUI gestures (tap, drag, long press, magnification, rotation), composing gestures, managing gesture state, or debugging gesture conflicts - comprehensive patterns for gesture recognition, composition, accessibility, and cross-platform support

Reference — AVFoundation audio APIs, AVAudioSession categories/modes, AVAudioEngine pipelines, bit-perfect DAC output, iOS 26+ spatial audio capture, ASAF/APAC, Audio Mix with Cinematic framework

subject segmentation, VNGenerateForegroundInstanceMaskRequest, isolate object from hand, VisionKit subject lifting, image foreground detection, instance masks, class-agnostic segmentation, VNRecognizeTextRequest, OCR, VNDetectBarcodesRequest, DataScannerViewController, document scanning, RecognizeDocumentsRequest

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.

This skill is a Swift 6 concurrency guide for actor isolation, `Sendable`, `@MainActor`, and async/await patterns. It includes developer-facing code examples that perform network requests (e.g., `URLSession.shared.data(from:)` to `https://swift.org`).

Use when debugging SwiftUI view updates, preview crashes, or layout issues - diagnostic decision trees to identify root causes quickly and avoid misdiagnosis under pressure

This skill is a Swift performance optimization guide covering COW, ARC, generics, collections, `Span`/`InlineArray`, and concurrency. No security-relevant behaviors detected.

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

Reference — Comprehensive Apple Human Interface Guidelines covering colors (semantic, custom, patterns), backgrounds (material hierarchy, dynamic), typography (built-in styles, custom fonts, Dynamic Type), SF Symbols (rendering modes, color, axiom-localization), Dark Mode, accessibility, and platform-specific considerations

This skill is a Swift Testing guide for writing and running unit tests, migrating from XCTest, and optimizing fast feedback. It includes example shell commands such as `cd MyAppCore` and `swift test` that instruct running local build/test commands; no credential access or data exfiltration is present.

Use when UI is slow, scrolling lags, animations stutter, or when asking 'why is my SwiftUI view slow', 'how do I optimize List performance', 'my app drops frames', 'view body is called too often', 'List is laggy' - SwiftUI performance optimization with Instruments 26 and WWDC 2025 patterns

Use when ANY iOS build fails, test crashes, Xcode misbehaves, or environment issue occurs before debugging code. Covers build failures, compilation errors, dependency conflicts, simulator problems, environment-first diagnostics.

Use when writing, running, or debugging XCUITests. Covers element queries, waiting strategies, accessibility identifiers, test plans, and CI/CD test execution patterns.