Both the Google Calendar and Office365 calendar integrations request permission to read from and write to your calendar events.
We request write access so that we can insert a link in the description for calendar events that are synced to a Charma workspace. The link takes you to the synced workspace and launches any video conference associated with the meeting. Links are only added to calendar events that are synced to a workspace on Charma.
Both calendar integrations are user-level. They only have access to the calendar events for the individual who connected the integration, not the calendar events of the individual's organization.