Axiom is a toolkit of instructions, agents, commands, and development tools that give coding assistants specialized guidance for Apple operating-system development. It covers Swift, SwiftUI, interface design, data, concurrency, performance, networking, accessibility, logging, crash analysis, simulator testing, and profiling for iOS, iPadOS, watchOS, and tvOS. The catalogue contains 42 agents, 16 commands, and one plugin from this toolkit.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add CharlesWiltgen/Axiom --skill axiom-healthgit clone --depth 1 https://github.com/CharlesWiltgen/AxiomWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/charleswiltgen/axiom/axiom-health)<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-health"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-health/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-health"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-health.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk warn
- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00045 | $0.01353 |
| Opus 5 | $0.00023 | $0.00677 |
| Sonnet 5 | $0.00009 | $0.00271 |
| Haiku 4.5 | $0.00005 | $0.00135 |
Grade A, and why
axiom-health scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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 |
Workout zones (heart-rate/power effort bands), live + retrospective OS27 |
See skills/workouts.md |
| WorkoutKit custom/planned workouts, scheduling, swimming workouts, previewing | See skills/workoutkit.md |
State of Mind, Medications API, symptom logging, menopausal state, wellbeing APIs OS27 |
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
What ships with it
8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 92 lines · 45 tokens per session scan A 336799b004dd
axiom-health is a skill published in the GitHub repository CharlesWiltgen/Axiom (1,155 stars, last pushed 3d ago), licensed MIT. It adds 45 tokens to every session and 1,353 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-06.
Other skills, from other repositories
healthmd-cli
Install and operate the standalone Health.md CLI and portable healthmd-mcp server on macOS, Linux, or Windows. Use when a user wants to pair an iPhone, configure Codex/Claude MCP, check direct readiness, query or chart typed health data, export Apple Health data, extract canonical JSON, manage durable jobs, automate…
healthkit
HealthKit: HKHealthStore, authorization, reading/writing health data, queries. Use when implementing app features related to healthkit.
healthkit
Read, write, and query Apple Health data using HealthKit. Covers HKHealthStore authorization, sample queries, statistics queries, statistics collection queries for charts, saving HKQuantitySample data, background delivery, workout sessions with HKWorkoutSession and HKLiveWorkoutBuilder, HKUnit, and…
vision
Guides you through implementing people-focused computer vision: subject segmentation, hand/body pose detection, person detection, and combining Vision APIs to solve complex problems.
vision-ref
Vision framework API, VNDetectHumanHandPoseRequest, VNDetectHumanBodyPoseRequest, person segmentation, face detection, VNImageRequestHandler, recognized points, joint landmarks.
sensorkit
Access ambient, motion, biometric, and interaction research data using SensorKit. Use when configuring sensor readers, handling authorization and study onboarding, fetching sample streams, managing user data deletion, or building research and clinical studies.