AlarmKit
Framework for scheduling alarms and countdown timers with custom UI, Live Activities integration, and focus/silent mode override. Prevents the most common mistakes: using the wrong authorization property name, omitting the Info.plist key, and forgetting the widget extension for countdown presentations.
When This Skill Activates
Use this skill when the user:
- Asks to add, fix, or review alarm or timer functionality
- Mentions AlarmKit, AlarmManager, or AlarmPresentation
- Wants to schedule one-time, repeating, or countdown alarms
- Asks about snooze, stop, or repeat buttons on alarm alerts
- Wants alarms to appear on Dynamic Island or Lock Screen (Live Activities)
- Mentions overriding Focus or silent mode for alarms
- Asks about AlarmAttributes or AlarmMetadata
Decision Tree
Choose the right reference file based on what the user needs:
What do you need?
|
+-- Schedule an alarm (one-time, repeating, or timer)
| --> scheduling.md
| +-- One-time alarm: Alarm.Schedule.relative + .repeats: .never
| +-- Repeating alarm: Alarm.Schedule.relative + .repeats: .weekly(weekdays)
| +-- Countdown timer: CountdownDuration (no schedule)
| +-- Authorization & Info.plist setup
| +-- Managing alarms: pause, resume, cancel
|
+-- Customize alarm UI (alert, countdown, paused screens)
| --> presentation.md
| +-- AlarmPresentation.Alert: title, stop, snooze/repeat buttons
| +-- AlarmPresentation.Countdown: title, pause button
| +-- AlarmPresentation.Paused: title, resume button
| +-- Custom buttons with AlarmButton
| +-- Tint color and metadata via AlarmAttributes
|
+-- Show alarm on Dynamic Island / Lock Screen
--> live-activities.md
+-- Widget extension with ActivityConfiguration
+-- AlarmAttributes conformance
+-- Custom AlarmMetadata protocol
API Availability
| API | Minimum Version | Reference |
|-----|----------------|-----------|
| AlarmManager | iOS 18 | scheduling.md |
| Alarm / Alarm.Schedule | iOS 18 | scheduling.md |
| AlarmPresentation (.alert, .countdown, .paused) | iOS 18 | presentation.md |
| AlarmAttributes | iOS 18 | live-activities.md |
| AlarmMetadata | iOS 18 | live-activities.md |
| AlarmButton | iOS 18 | presentation.md |
| CountdownDuration | iOS 18 | scheduling.md |
| alarmUpdates async sequence | iOS 18 | scheduling.md |
| authorizationUpdates async sequence | iOS 18 | scheduling.md |
Top Mistakes -- Quick Reference
| # | Mistake | Fix | Details |
|---|---------|-----|---------|
| 1 | Using .authorizationStatus instead of .authorizationState | The property is AlarmManager.shared.authorizationState -- there is no authorizationStatus | scheduling.md |
| 2 | Forgetting NSAlarmKitUsageDescription in Info.plist | Add the key with a user-facing string before calling requestAuthorization() | scheduling.md |
| 3 | Creating countdown timer with a schedule | Timers use CountdownDuration only -- do not pass a schedule | scheduling.md |
| 4 | Missing widget extension for countdown presentations | Countdown and paused UI requires an ActivityConfiguration(for: AlarmAttributes.self) widget | live-activities.md |
| 5 | Not persisting alarm UUIDs | Store the Alarm.id (UUID) so you can pause, resume, or cancel later | scheduling.md |
| 6 | Not observing alarmUpdates for state sync | Use the alarmUpdates async sequence to keep local state in sync with the system | scheduling.md |
Review Checklist
When reviewing AlarmKit code, verify:
- [ ] Info.plist --
NSAlarmKitUsageDescriptionis present with a meaningful description - [ ] Authorization --
requestAuthorization()is called before scheduling; denial is handled gracefully - [ ] Correct property -- uses
.authorizationState, not.authorizationStatus - [ ] Alarm ID persistence -- alarm UUIDs are stored (e.g., UserDefaults, SwiftData) for later management
- [ ] State observation --
alarmUpdatesasync sequence is used to keep UI in sync - [ ] Widget extension -- exists if countdown or paused presentations are used
- [ ] Error handling --
schedule(),pause(),resume(),cancel()calls handle errors - [ ] System limits -- code accounts for the system limit on number of active alarms
- [ ] Real device testing -- alarms are tested on physical devices, not just Simulator
Reference Files
| File | Content | |------|---------| | scheduling.md | Authorization, one-time/repeating/timer creation, managing alarms, observing updates | | presentation.md | Alert, countdown, paused UI customization, buttons, tint color | | live-activities.md | Widget extension, AlarmAttributes, AlarmMetadata, Dynamic Island |