# Instant agent inboxes

An address on the platform domain, without your DNS.

2 min read. HTML: https://sendwithflare.com/help/agent-inboxes/

## Create one in Agents & MCP

Give this agent an inbox creates an address on the platform domain (by default `agents.sendwithflare.com`). The local part is lowercase, unique, and reserved names are blocked.

Receive, MCP, and the developer API use the same mailbox as a custom-domain address. Sending stays off until the platform outbound provider is configured. The screen does not say ready to send until that is true.

## Use your own domain

A paying customer who wants every address at their own domain, such as `support@theirdomain.com`, adds that root domain in [Sending domains](/help/add-a-sending-domain/). The domain must already be an active Cloudflare zone. FlareMail then enables the catch-all, so agent mail and human mail on that domain arrive in the same account. Scope the Agent Key to the mailbox the agent should use.

That catch-all works because `theirdomain.com` is the zone itself. A name underneath it, such as `agents.theirdomain.com`, cannot be a separate zone on a Free, Pro, or Business account, and Email Routing will not catch every address on that subdomain. Put the agent address on the root domain.