SKILL.md
AI Agent Email Inbox
Overview
This skill covers setting up a secure email inbox that allows your application or AI agent to receive and respond to emails, with content safety measures in place.
Core principle: An AI agent's inbox receives untrusted input. Security configuration is important to handle this safely.
The skill builds the agent on a Resend Inbox. An inbox groups email into threads, and your agent replies inside the thread with one call. Resend sets the recipients and the threading headers. If the user has no custom domain, or their plan has no inbox available, use Receiving without an inbox instead. The security levels are the same for both.
Why Webhook-Based Receiving?
Resend uses webhooks for inbound email, meaning your agent is notified instantly when an email arrives. This is valuable for agents because:
- Real-time responsiveness — React to emails within seconds, not minutes
- No polling overhead — No cron jobs checking "any new mail?" repeatedly
- Event-driven architecture — Your agent only wakes up when there's actually something to process
- Lower API costs — No wasted calls checking empty inboxes