# Rex — an AI coach that knows your data and acts on it

Most fitness apps show you charts and leave the interpretation to you. Reps includes an AI coach, Rex, that you can actually ask about your own training and recovery — and get an answer built from your data, not a generic tip pulled from a blog.

## Ask it anything about your body

Ask Rex "why is my recovery low today?" or "should I train legs?" and it answers using your logged sleep, training, and recovery data — not canned advice. Rex watches your sleep, training, and recovery through the day, so it has context before you even ask.

## Built around your recovery

Rex's coaching isn't limited to answering questions — it's used to shape the workouts Reps builds for you, adjusting around how recovered you actually are rather than a fixed program that ignores today's readiness. Training plans can also be described in plain language (for example, a week that's light on legs) and Reps builds around that instead of forcing a rigid template.

## Where it runs

Where your iPhone supports it, Reps' AI reasoning — including the Readiness Score and parts of Rex's coaching — runs on-device using Apple's on-device language model, so that reasoning doesn't require a network round-trip. Rex's chat can still use a cloud-based model for more complex or open-ended questions when needed; it isn't a blanket on-device-only system, but the health data behind the coaching stays out of analytics either way.

## Personality

Rex has a bit of personality — a calm, occasionally dramatic coaching voice, not just a chatbot skin. But the substance behind it is grounded in your actual data: your HRV, sleep, training load, logged meals, and workout history.

## Not medical advice

Rex's coaching is training and recovery guidance, not medical advice. It doesn't diagnose conditions or make injury-prevention guarantees.

[Download Reps on the App Store](https://apps.apple.com/app/id6746460451)