Shared Tasks keeps one list for everyone who lives together. Recurring chores rotate between people on their own, and tasks tied to a calendar event show up only once that event has actually happened — so the list reflects what really happened, not what a rule predicted.
Sign-in uses your Google account. Nothing is posted anywhere on your behalf.
Everyone in the household sees the same tasks, and each task says who it belongs to.
Set a chore to repeat on a schedule and it alternates between people automatically, so nobody has to keep score.
Link a task to a calendar event and it appears only after the event actually happens — skip a week and no task appears.
A companion iOS app adds tasks in a couple of taps, and queues them if you are offline.
A recurring task written as a fixed schedule goes wrong the moment real life moves: a lesson gets rescheduled, a week gets skipped, and the reminder fires anyway. So a task can instead be attached to an event on your Google Calendar.
To do that, Shared Tasks asks for read-only access to your calendar, and only if you choose to link a task to an event. It reads the title of the event you picked and the start and end times of its occurrences — enough to know whether that event has finished — and creates the task afterwards. It never writes to your calendar, never reads the contents of other events, and never shares calendar information with anyone.
You can withdraw that access at any time from your Google account permissions, and the rest of the app keeps working.