Anyone who's wired an autonomous agent into email and calendar the traditional way knows the identifier sprawl: an OAuth client ID, a refresh token per user, a Gmail-specific message ID format, a Microsoft Graph calendar ID, and a webhook subscription ID for each — all with different lifetimes, all able to break independently. Half your "integration" code is really identifier bookkeeping.
Nylas Agent Accounts collapse all of that into one value. When you create an account (the feature's in beta), the response hands you a grant_id, and that single string is the handle for everything the agent does — mail, calendar, contacts, attachments, and the webhooks reporting on all of them.
One ID, the whole surface
Every operation addresses the same path family, /v3/grants/{grant_id}/*:
POST /v3/grants/{grant_id}/messages/send # send mail
