Last updated: 9 October 2026

Onyx: Fitness & AI Coach is made by The Miller Brand ("we"). This policy explains what Onyx reads, what leaves your iPhone, who handles it, and how to remove it. The short version: your health data lives on your iPhone. Some of it goes to our AI provider, Anthropic, only when you use a feature that needs it, only after you've given Onyx permission, and only to answer you. It is never sold or used for advertising.

1. What Onyx reads from Apple Health

Only what you allow in the Health permission sheet, and only to compute your scores, trends and Coach's reads:

• Activity: steps, active and resting energy, exercise and stand time, distance (walking, running, cycling, swimming), stair speed, workouts.
• Heart: heart rate, resting heart rate, heart rate variability, walking heart rate, cardio fitness (VO₂ max), high/low heart rate and irregular rhythm notifications, AFib burden.
• Sleep and recovery: sleep stages and times, respiratory rate, sleeping wrist temperature.
• Body: weight, height, BMI, body fat, lean mass, waist circumference.
• Mobility: walking speed, step length, asymmetry, double support, steadiness, six-minute walk distance, falls.
• Other health records you may have in Health: blood pressure, blood glucose, menstrual flow (to put recovery in the context of your cycle), water, caffeine and alcoholic drinks, mindful minutes.
• Characteristics: date of birth and biological sex, used for calorie and heart-rate calculations.
• Health Records lab results, only if you choose "Connect Health Records": the lab results your provider has shared with Apple Health. Onyx reads them into your Labs, on your iPhone and in your iCloud; they don't pass through our server to get there.

Items in bold are sensitive. Onyx does not use any Health data for advertising or marketing, and never sells it.

2. What Onyx writes to Apple Health

When you ask it to: workouts you record (with heart rate, distance and, for outdoor sessions, the route), weigh-ins and body measurements you enter, and — unless you turn it off in Settings → Your data — the meals you log, with their calories and nutrients. Edits and deletions in Onyx are reflected in Health.

3. Location

Onyx uses your location only while a run, walk, ride or hike you started in Onyx is in progress, to measure distance and pace and draw the route. The route is saved to Apple Health with the workout. It is not sent to our server.

4. On your iPhone, and Apple Intelligence

Scores, trends, the notification plan, food scores and most of Coach's written reads are computed on your iPhone. Where Apple Intelligence is available, Onyx's written summaries — and the reading of a training goal you type in your own words — are produced by Apple's on-device model. We don't receive that data.