From the RunCoached guide
Your plan is built on your phone.
Your plan uses your Apple Health data on your phone.
On your phone
Coach reads the runs your tracking setup writes to Apple Health. Your training history is processed on your device. It is not uploaded to DVDA Games or an external AI service.
Rules and text input
Rules choose the sessions, distances, paces, and limits. When available, Apple's on-device model is used only to read and categorize text you enter. It extracts details such as recurring runs for your plan.
Optional device location
When you enable location, Coach requests its own When In Use permission at neighborhood-scale accuracy. This helps select a forecast area and notice travel away from your usual running area. Health permission for workout routes is separate.
When location is unavailable
Coach can infer your usual running area from workout route starts. When the area is ambiguous, it asks where you will run. Without location or route history, it cannot infer an unseen destination. A stored forecast for the same place and hour can be used when a refresh fails.
When you send feedback
Coach opens an email in your own Mail. You see all of it before you send it. You can add a summary of your setup, with no routes, dates or heart-rate readings. You can also add the latest crash report that iOS recorded on your phone. Coach sends nothing by itself.
Weather uses a separate service
Forecast requests send the selected latitude and longitude and forecast time to Apple Weather. Coach does not attach your training summary. Apple also resolves area names and time zones from locations. Coach uses no other weather service.
Continue reading.
What Coach needs from Health
Runs in Apple Health start your plan. Route and heart-rate data add more guidance.
When heart rate goes missing
Why a watch can stop recording heart rate, and what Coach does then.
Which zones fit your runs
How Coach chooses between threshold zones and heart-rate reserve zones.