Focus filters

A Focus is the user telling macOS what they are doing. A filter is Magical being told, so that turning on a Work Focus stops personal meetings interrupting without also hiding the calendar.

What a filter silences

A filter asks two questions: which accounts you are working in, and then which of their calendars matter. Both start with everything on, so a filter nobody has touched silences nothing. Turn an account off and every calendar it has goes quiet; leave it on and you can still turn its calendars off one at a time.

A silenced calendar loses these:

Every glanceable surface reads one list, so none of them can contradict another: a title counting down to a lunch the agenda does not list reads as a bug whichever half is right, and a Focus that quietens the popover while the title still announces the same meeting has not done what was asked.

An event sits on several calendars at once, and it goes quiet only when the filter silences every one of them. A Work Focus that silences a recruiting calendar has not asked to lose an interview the user is attending on their own calendar; see calendar-wire-format.md for why the event carries all of them.

An account is silenced when nothing it has is left on, whether because the filter turned the account off or because its calendars went one by one. That is the only account-level state there is, because a switcher segment is one account and cannot be half-disabled:

Prevent Access to Silenced Accounts moves an account from the first column to the second, and it never applies to the account you are looking at: a filter that silenced every account would otherwise grey out all of them at once and leave the window with nowhere to go.

Everything else stays where it was. The account is still in the switcher, the calendar is still in the popover's filter list, and the events are still polled, cached and scheduled.

How the filter reaches the app

The intent, the state file and the distributed notification are the shared mechanism in ../shared/focus-filters.md. The banner is filtered by MagicalHelper, the only thing that posts a Magical banner, rather than by an appContext NSPredicate over each notification: the helper checks the filter first, so the predicate could only agree or be out of date, and the snapshot it would carry is taken when the filter is configured and so cannot name a calendar created since.

The picker's constraints, the accounts-and-calendars model, the prefixing rule, the rule that a Focus only ever silences, the scheduler being left unaware, the packaging requirements and the known limitation are all shared and in ../shared/focus-filters.md.

Picker behaviour when a calendar is added

The picker cannot hold a button, so "everything in this account" is a separate Accounts parameter rather than a row among the calendars, where it would read as one more calendar. The calendar list is deliberately not narrowed to the accounts still on: IntentParameterDependency would let MagicalCalendarQuery read Accounts and filter itself, but making the entity set depend on another parameter re-resolves it and loses the stored selection, so every calendar in a saved filter comes back unticked on the next edit.