ActivityKit

Live Activities — glanceable, real-time updates on the Lock Screen and in the Dynamic Island. The deep API reference — setup, attributes, the full start/update/end lifecycle, push tokens, the widget-extension UI, and the complete delivery-tracker example — lives in references/guide.md. This file is the decision and discipline layer: read it first, open the guide for specifics.

Dials

Set these explicitly at the start; they change what "correct" means.

1. UPDATE_CHANNEL — local (default; foreground app calls activity.update(_:), cheap, no server) · push-token (server drives updates via APNs; observe activity.pushTokenUpdates, requires the push entitlement and a server). Pick push-token whenever the activity must move while the app is suspended.
2. START_MODE — in-app (default; Activity.request while the app is foregrounded) · push-to-start (server starts the activity remotely via Activity.pushToStartTokenUpdates, iOS 17.2+; no app launch needed).
3. DYNAMIC_ISLAND — minimal (compactLeading/compactTrailing + minimal only) · full-expanded (also implement all DynamicIslandExpandedRegions for the long-press/active presentation). Even minimal must still supply compact + minimal — they are not optional.

When to use

Building or reviewing any Live Activity: starting/updating/ending an Activity, defining ActivityAttributes/ContentState, wiring push or push-to-start tokens, or laying out the Lock Screen / Dynamic Island presentations. The presentation itself is a WidgetKit ActivityConfiguration inside a widget extension — for general widget/timeline work reach for widgetkit.

Core rules