Two separate things live under Availability, and they run in opposite directions.
Neither is required. Both can be on at once.
Reading your calendar
Connect Google Calendar under Your own calendar asks Google for one thing: the hours you are busy. Google Calendar is the only provider — no Outlook, iCloud or CalDAV.
The Google account you connect doesn’t have to be the account you sign in with, and connecting one doesn’t change how you sign in.
Free/busy only
The free/busy scope returns intervals and nothing else: no title, no guests, no location, no description, no attachment, no organiser. Disconnecting deletes what was stored.
What it does to your slots
A busy hour closes that slot for clients. It does not stop you: your connected calendar isn’t consulted when you book one of your own clients in, though your grid still draws the busy hour.
Two things do still stop you: an existing Open Therapy session at the same time, and the buffer you keep between sessions.
Sync runs hourly
A pass reads a window of your calendar and rewrites it whole, so an appointment moved, shortened, declined or deleted isn’t in the next answer, and the hour comes back onto the market.
The panel says when the calendar was last checked and how many things on it are holding hours.
There’s no “sync now” button, and no live push from Google.
When a conflict appears after a booking
A booked session stays booked. Busy hours close slots that haven’t been taken; they never cancel one that has.
If you accept a meeting on top of an existing session, the client is told nothing and it’s yours to resolve: reschedule the session, or move the other thing. See Managing sessions.
If the connection breaks
A grant can be withdrawn, in your Google account or by Google. The connection then stops refreshing and the panel shows the error. Reconnect from the same place; until you do, your published availability is governed by your hours alone.
Publishing your sessions out
Calendar feed gives you a URL to subscribe to from Google Calendar, Apple Calendar, Outlook or anything else that takes an ICS feed. It is one-way and read-only: editing an event in your calendar app changes nothing here, and deleting one doesn’t cancel a session.
The feed carries the time, the service and a first name, and travels as a URL with a random token in it, so anyone holding it can read the feed.
Rotate issues a new URL and breaks the old one immediately. Do that if the link has been shared, indexed, or added to a calendar you no longer control, then re-subscribe.
A subscribed feed sits in whatever account you added it to. Adding it to a shared or work calendar
puts client first names and session times in front of whoever else can see that calendar.
