You give your AI agent a real mailbox, it sends its first batch of email, and half of it lands in spam. The agent did nothing wrong. The domain did — it's new, it has no sending history, and mailbox providers treat an unknown domain that suddenly sends volume the same way they treat a spammer. Deliverability is the work of proving the mail is really yours, sending at a pace providers trust, and watching the signals that say whether recipients want it.
An Agent Account sends from a domain you own, so its inbox placement is yours to manage like any other mail from your company. This post is a practical playbook for getting and keeping an agent in the inbox, from two angles: the HTTP API for your backend, and the Nylas CLI for the terminal. I work on the CLI, so the terminal commands below are the ones I reach for when I'm wiring up monitoring.
The deliverability checklist
Five things decide whether an Agent Account reaches the inbox, and you can act on all of them before sending at volume. Work them in order — authentication first, because nothing else matters if recipient servers can't confirm the mail is yours, then pace and monitoring once mail is flowing.
Authenticate the domain with DKIM and SPF as part of domain verification.
