I want to create an Event on a microsoft calendar via the Create Event Graph API. When attendees are included, they automatically get emailed invitations which is fine. But what I don't want is to have attendees get the offer to propose a new time. When emailing a .ics icalendar file, X-MICROSOFT-DISALLOW-COUNTER:TRUE may be included and that disables that option. I'm trying to find a way to do that with the Create Event API. I do not see anything like that. There is some reference to custom attributes that can be sent but little detail on how they are defined so I don't know if maybe the custom attributes could be used to get equivalent functionality to the option when using a .ics file.

When a do a create event call, the attendees get an email with a notification of the event but the Propose New Time feature is enabled. I do not want it enabled. Would need to add something to the request below.

{
  "body": {
    "content": "Let's talk about some stuff",
    "contentType": "HTML"
  },
  "end": {
    "dateTime": "2025-03-11T15:00:00",
    "timeZone": "Pacific Standard Time"
  },
  "isOnlineMeeting": true,
  "location": {
    "displayName": "Meet Online in Teams Meeting"
  },
  "onlineMeetingProvider": "teamsForBusiness",
  "start": {
    "dateTime": "2025-03-11T14:00:00",
    "timeZone": "Pacific Standard Time"
  },
  "subject": "Meet about next steps"
}