alarmkit

AlarmKit

Review and write AlarmKit code for correct authorization, alarm scheduling, presentation configuration, and Live Activities integration.

Responsibility

Owns: AlarmManager, Alarm, AlarmPresentation, AlarmAttributes, AlarmMetadata, countdown timers, alarm authorization, alarm observation, Live Activities for alarm UI.

Does NOT own: Local notifications (UserNotifications), background task scheduling (BGTaskScheduler), timer UI design (SwiftUI skill), HealthKit or domain-specific timing.

Core Principles

1. Authorization first. Always request and check authorization before scheduling. Use authorizationState (NOT authorizationStatus).
2. Widget extension required for countdowns. Countdown presentations need a widget extension to display in Dynamic Island and Lock Screen.
3. Observe alarm updates. Use alarmUpdates async sequence to keep app state in sync — alarms can be dismissed or modified by the system.
4. Persist alarm IDs. Store UUIDs you create to manage alarms later. The system does not provide a way to query "your" alarms by app context.
5. System limits apply. There is a cap on the number of alarms per app. Design for it.
6. Test on device. Alarm behaviour (notifications, Live Activities, sound) only works fully on physical devices.

Review Process

1. Check authorization handling → references/alarmkit-patterns.md
2. Check alarm creation patterns (one-time, repeating, countdown)
3. Check presentation configuration (alert, countdown, paused states)
4. Check alarm management (schedule, pause, resume, cancel)
5. Check observation (alarmUpdates, authorizationUpdates)
6. If using countdowns, verify widget extension exists

Red Flags

Anti-Pattern	Problem	Fix
Using authorizationStatus	Wrong property name	Use authorizationState
No authorization check before scheduling	Runtime failure	Request auth first, handle denial
Countdown without widget extension	No Dynamic Island / Lock Screen UI	Add widget extension
Not observing alarmUpdates	App state goes stale	Observe async sequence
Not persisting alarm UUIDs	Cannot manage alarms later	Store UUIDs in app storage

References

• references/alarmkit-patterns.md — Authorization, snooze mechanism, alarm types, presentation, management, SwiftUI ViewModel, Live Activities
• WWDC25-230 — AlarmKit introduction session