What permissions does Monty request, exactly?

Read, send, and manage messages on the specific mailbox you connect — that's what lets Monty see incoming lead replies, place drafts or sends in the thread, and keep it organized. It does not request access to your contacts, files, or any other mailbox in your organization, and the mailbox connection never asks for calendar access (if you later enable meeting booking, that's a separate calendar-only consent you approve explicitly). You can see the exact scopes on the provider's consent screen before you accept, and revoke them at any time from your Google account security page.