The assistant on your wrist: Apple Watch and Live Activities
A 40-millimetre screen has no room for a summary. It has room for one sentence, and that sentence has to be the right one.
An assistant on the phone competes with everything else on the phone. On the watch it competes with nothing, which is why it is the place where getting it right or wrong shows most. It is also where there is least room for error: send three bad alerts in a row and the user turns notifications off and never comes back.
The constraint is the design
On the desktop you can afford a panel with five sections. On the wrist you have one line and perhaps a button. That forces an answer to a question you can dodge on a big screen: out of everything I know right now, what is the one thing that deserves a buzz?
In practice it is almost always one of three things: the next thing you have to do, the thing about to fall due, or something that changed in a plan you had already accepted. Everything else can wait until you pick up the phone.
Live Activities: useful when there is a countdown
Live Activities are built for something in progress with a predictable end — a delivery on its way, a match, a timer. They fit the part of the day shaped like a countdown: the meeting starting in twenty minutes, this afternoon's deadline, the journey you need to leave for.
They fit badly with everything else. A Live Activity showing "you have 12 tasks" is not in progress: it is a widget in disguise, occupying privileged space and never changing. They are worth reserving for what genuinely moves on its own, and leaving the rest to the widget, where it does not intrude.
Sync little, sync well
The watch should not talk to the server. It should talk to the phone, and the phone should already have the data. It is faster, it uses less battery and, above all, it keeps the watch working with no signal, which is half the times you look at it.
That means deciding what gets sent: not the whole day, but the small slice that fits on screen. A handful of already-resolved fields — the text that will be shown, the time, the state — rather than the full data model for the watch to chew through. The logic stays on the phone; the watch only draws.
The bar
A good wrist assistant is measured by one thing: how often you raise your wrist and find exactly what you were about to look up on your phone. If the answer is "nearly always", it was worth building. If it is "sometimes", the watch becomes one more place to check, which is precisely the opposite of the point.
You can see how we are building it in Madrugo, and why the day's summary is computed before you ask for it in the calendar and tasks articles.