Design Apple System Experiences with HIG

Apple HIG: System Experiences codifies Apple Human Interface Guidelines principles for surfaces that show app content outside the app itself, checking for an existing .claude/apple-design-context.md before asking redundant questions. Widgets should show a relevant subset of information (not everything), support multiple sizes as distinct thoughtful layouts rather than scaled versions of one design, and deep-link on tap to the relevant content rather than the app's root screen. Live Activities track events with a clear start and end (deliveries, scores, timers, rides), designed for both Dynamic Island and Lock Screen, staying timely and ending promptly when the event concludes.

Use it when deciding which system surface fits a use case and how to design for it: notifications must respect user attention (no promotional or low-value pushes), be actionable and self-contained with enough context to act without opening the app, and use threading/grouping; complications show focused data at the smallest useful representation, support multiple families, and budget updates wisely; Home Screen Quick Actions surface the 3-4 most common tasks with short titles and SF Symbol icons; tvOS Top Shelf features enticing content like new episodes; App Clips deliver instant, focused functionality within a strict size budget, loading without an App Store download and offering full app install only after the immediate task; App Shortcuts surface key actions to Siri and Spotlight with natural, conversational trigger phrases.

Output follows a fixed structure: which system-experience surface best fits the use case, a content strategy (what to display, priority, what to omit), update frequency respecting system budget constraints, which size/family variants to support and how layouts adapt, and deep-link behavior on tap. Before recommending, it asks what information needs to surface outside the app, which platform, how frequently the data updates, and the primary glanceable need.

A reference index points to detailed docs per surface - widgets, Live Activities, notifications, complications, Home Screen quick actions, top shelf, App Clips, watch faces, and App Shortcuts - and cross-references three related skills: progress indicators in widgets/Live Activities, interaction patterns like Digital Crown for complications, and platform technologies (Siri for App Shortcuts, HealthKit for complications, NFC for App Clips).

iOS/watchOS/tvOS developers and designers deciding which glanceable system surface to build for a feature and how to design its content, sizing, update cadence, and deep-linking correctly per Apple's HIG.