Apple Watch app
From the app’s English Help & Guide · Reference release 1.0.13
If you have an Apple Watch paired with your iPhone, its Supported companion app installs automatically by default. If it is missing, open the Watch app on your iPhone, tap My Watch, scroll to Available Apps, then tap Install next to Supported.
The watch app shows the same list of people you have on your phone, with each person's current day rating, flare/crash flags, and a short status. Tap a person on the watch to see a fuller view: today's rating, a plain-English energy signal ('Doing okay', 'Running low', etc.) when their tracker app provides one, and conditions.
The watch deliberately uses everyday phrases instead of raw spoon counts so the signal makes sense without knowing the in-group vocabulary.
The watch app reads data your phone has already received — it doesn't fetch from CloudKit directly. Open Supported on your phone now and again, especially after travelling or being out of signal, to make sure the watch has fresh data.
Demo data populates the watch automatically once your phone is in demo mode.