Connect legacy tools to an agent mailbox over IMAP/SMTP

Most "AI email" integrations assume everything on the other side speaks REST. You wire up a webhook, you call POST /messages/send , and you move on. That works right up until you remember how much of your stack doesn't speak REST and never will: the ticketing system that ingests mail over IMAP, the backup script your predecessor wrote in 2014, the monitoring tool that only knows how to send SMTP, the compliance archiver that polls a mailbox every five minutes. None of those are getting rewritten to call an HTTP API for your demo. So here's the trick that makes a Nylas Agent Account genuinely useful in a real environment: it's not API-only. You can expose the same mailbox over IMAP and SMTP submission , hand the host, port, and credentials to one of those legacy tools, and let it read and send like it's talking to any old mail server. Meanwhile your agent drives that identical mailbox over the v3 API. Both surfaces hit one storage layer. A flag, move, or delete on either side shows up on the other within seconds. I work on the Nylas CLI, so the terminal commands below are the exact ones I reach for. As usual I'll show both angles for every operation — the raw curl against the API and the nylas command — because half the point of an Agent Account is that you can mix them freely. What you actually get An Agent Account is just a grant . It has a grant_id , and that grant_id works with every grant-scoped endpoint you already know — Messages, Drafts, Threads, Folders, Attachments, Contacts, Calendars, Events. There's nothing new to learn on the data plane. The IMAP/SMTP layer doesn't change that model. It adds a second door into the same room: One mailbox, two protocols. The API and the IMAP/SMTP server are two front-ends over the same backend. There is no sync job, no eventual-consistency window worth worrying about, no "API mailbox" versus "client mailbox." It's one mailbox. Legacy tools just work. Anything that can authenticate to an IMAP server with a username and pas