# Understand agent addresses

> Each agent gets one primary address, name@atmark.ai. You can't change it after the agent is created.

The address you pick when creating an agent is its **primary address**. The agent receives mail at this address and, unless told otherwise, sends from it.

## Rules

- The format is `name@atmark.ai`. The name uses lowercase letters, digits, `.`, `_`, and `-` only. See [Create an agent](https://docs.atmark.ai/en/agents/create#address-rules) for the full rules.
- **You can't change it after the agent is created.** If you need a different address, create a new agent.
- Stopping an agent doesn't free its address, and the address is never reissued to anyone else.

## Where to find it

- Under the agent's name in the agent list
- Next to the title of the agent's **Email** screen
- In `from_address` when the agent calls `get_my_policy`

## Incoming mail

Mail sent to the primary address passes the inbound policy before it reaches the agent's inbox. Blocked mail is quarantined. See [Choose which mail your agent sees](https://docs.atmark.ai/en/email/receiving).

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Source: https://docs.atmark.ai/en/email/addresses · Last updated 2026-09-27