HealthKit and WorkoutKit
You MUST use this skill for ANY HealthKit or WorkoutKit development including authorization, data queries, background delivery, workout sessions, planned workouts, wellbeing APIs (State of Mind), Medications, and Health Records.
Quick Reference
| Symptom / Task | Reference |
|---|---|
HealthKit framework model, HKHealthStore, data types, sample vs characteristic data | See skills/fundamentals.md |
Capability setup, requestAuthorization, purpose strings, read-asymmetry, privacy | See skills/authorization-and-privacy.md |
HKSampleQuery, Swift Concurrency query APIs, HKStatisticsCollectionQuery, sample writes | See skills/queries.md |
Anchored queries, observer queries, HKDeletedObject, background-delivery entitlement | See skills/sync-and-background.md |
HKWorkoutSession, HKLiveWorkoutBuilder, recovery, multi-device, iOS/iPadOS/watchOS workout tracking | See skills/workouts.md |
| WorkoutKit custom/planned workouts, scheduling, swimming workouts, previewing | See skills/workoutkit.md |
| State of Mind, Medications API, symptom logging, wellbeing APIs | See skills/wellbeing-and-medications.md |
| Health Records (FHIR), Mobility Health App, motion-based health | See skills/clinical-and-mobility.md |
Cross-Suite Routes
These topics overlap with HealthKit/WorkoutKit but live in separate suites:
watchOS presentation
- Watch-specific workout presentation (Always On, Smart Stack), complication surfaces → See axiom-watchos
- Workout app structure on Apple Watch → See axiom-watchos (
skills/platform-basics.md)
Concurrency
- Swift 6 concurrency, actors, Sendable → See axiom-concurrency
- HealthKit queries bridging to Swift Concurrency →
skills/queries.mdis the canonical example
SwiftUI
- Charts rendering for health data → See axiom-swiftui
@Observableview models for health data → See axiom-swiftui
Data and sync
- General cross-platform sync patterns (CloudKit, GRDB) → See axiom-data
- HealthKit anchored/observer queries as a generalizable sync mechanism →
skills/sync-and-background.md
Security and privacy
- Keychain storage, encryption, data-protection entitlements → See axiom-security
Conflict Resolution
axiom-health vs axiom-watchos: For workout apps on Apple Watch:
- Use axiom-health for
HKWorkoutSessionlifecycle,HKLiveWorkoutBuilder, recovery APIs, multi-device mirroring — these are HealthKit concepts, not watch concepts - Use axiom-watchos for watch-specific presentation: Always On display, Smart Stack placement, watchOS background mode coordination
- Both apply for a watch-native workout app — start with axiom-health for session lifecycle, then axiom-watchos for presentation
axiom-health vs axiom-concurrency: For HealthKit query patterns:
- Use axiom-health for which query type to choose and HealthKit-specific gotchas
- Use axiom-concurrency for general Swift 6 actor isolation rules that apply to query callbacks
axiom-health vs axiom-data: For change-tracked data synchronization:
- Use axiom-health for
HKAnchoredObjectQuery,HKObserverQuery,HKDeletedObject - Use axiom-data for application-level data sync across devices (CloudKit, GRDB, SwiftData)
Decision Tree
digraph health {
start [label="HealthKit / workout task" shape=ellipse];
what [label="What area?" shape=diamond];
start -> what;
what -> "skills/fundamentals.md" [label="framework basics, data types"];
what -> "skills/authorization-and-privacy.md" [label="permissions, purpose strings, privacy"];
what -> "skills/queries.md" [label="reading data, rollups, writes"];
what -> "skills/sync-and-background.md" [label="change tracking, background delivery"];
what -> "skills/workouts.md" [label="HKWorkoutSession, live workouts"];
what -> "skills/workoutkit.md" [label="planned/custom workouts"];
what -> "skills/wellbeing-and-medications.md" [label="State of Mind, Medications"];
what -> "skills/clinical-and-mobility.md" [label="Health Records, Mobility"];
what -> "axiom-watchos" [label="watch-specific presentation"];
what -> "axiom-concurrency" [label="general actor isolation rules"];
what -> "axiom-swiftui" [label="Charts, data visualization"];
}Resources
WWDC: 2019-218, 2020-10182, 2020-10184, 2020-10664, 2021-10009, 2021-10287, 2022-10005, 2023-10016, 2023-10023, 2024-10084, 2024-10109, 2025-321, 2025-322
Docs: /healthkit, /healthkit/about-the-healthkit-framework, /healthkit/authorizing-access-to-health-data, /healthkit/protecting-user-privacy, /healthkit/reading-data-from-healthkit, /healthkit/running-queries-with-swift-concurrency, /healthkit/executing-anchored-object-queries, /healthkit/executing-observer-queries, /healthkit/hkworkoutsession, /healthkit/hklivewobuilder, /workoutkit, /healthkit/accessing-health-records
Skills: axiom-watchos, axiom-concurrency, axiom-swiftui, axiom-data, axiom-security