An AI agent with its own mailbox reacts to whatever lands in it. That's the point, until a spam blast, a mailer-daemon loop, or an auto-reply triggers the agent into answering noise. The same goes the other way: an agent composing mail on its own can address the wrong person, leak to a test domain that slipped into production, or email a competitor because nobody told it not to. A human would catch these. An agent needs guardrails encoded somewhere it can't skip.
Agent Accounts ship three admin resources for exactly this: Policies bundle limits and spam settings, Rules match mail on the way in or out and run actions like block or assign_to_folder, and Lists are reusable collections of domains or addresses that rules reference. This post covers all three from two angles: the HTTP API for your backend, and the Nylas CLI for inspecting and managing policies and rules from the terminal. Lists, workspaces, and the rule-evaluations audit log are API-only for now. I work on the CLI, so the terminal commands below are the ones I reach for.
How Policies, Rules, and Lists fit together
The three resources form a chain, and a workspace ties it to your accounts. A List holds values like domains or addresses. A Rule references lists through the in_list operator and describes conditions and actions. A Policy bundles limits and spam settings. A workspace carries one policy_id plus an array of rule_ids, and every Agent Account in that workspace inherits both.
