How do I give an AI agent its own email address?

Create a mailbox for it on a domain you own with an email infrastructure provider that has an API, such as Mektup. Point the mailbox's webhook at your agent so it hears about new mail, and let it reply through the API or MCP.

Should the agent use my main domain?

Either works. A subdomain like agents.yourcompany.com keeps your people's mail separate and lets you start without touching your main domain's MX records.

How do I stop the agent from answering spam or tricks?

Mektup filters incoming spam, and mail from senders you block never fires the webhook. Still treat every email as untrusted input: don't let instructions inside a message change what the agent is allowed to do, and draft instead of send for anything unusual.

How to give an AI agent its own email address

What you need

A domain you control, or a subdomain of it.
A Mektup account and an API key (Dashboard, API keys).
A public HTTPS URL for your agent to receive webhooks.

1. Create the domain, the mailbox and the webhook

export MEKTUP_API_KEY=mek_live_...
API=https://api.usemektup.com/v1

# 1. the domain (or a subdomain just for agents)
curl -X POST $API/domains -H "Authorization: Bearer $MEKTUP_API_KEY" \
  -H "Content-Type: application/json" -d '{"domain": "agents.yourcompany.com"}'
# add the records it returns at your DNS host, then:
curl -X POST $API/domains/agents.yourcompany.com/verify -H "Authorization: Bearer $MEKTUP_API_KEY"

# 2. the agent's mailbox
curl -X POST $API/domains/agents.yourcompany.com/mailboxes \
  -H "Authorization: Bearer $MEKTUP_API_KEY" -H "Content-Type: application/json" \
  -d '{"localPart": "ada"}'

# 3. where new mail should go
curl -X PUT $API/domains/agents.yourcompany.com/mailboxes/ada/webhook \
  -H "Authorization: Bearer $MEKTUP_API_KEY" -H "Content-Type: application/json" \
  -d '{"url": "https://your-agent.example.com/inbound"}'
# keep the "secret" from the response

2. Write the agent

agent.py (FastAPI)

import hashlib, hmac, json, os, requests
from fastapi import FastAPI, Request, HTTPException, BackgroundTasks

app = FastAPI()
API = "https://api.usemektup.com/v1"
KEY = os.environ["MEKTUP_API_KEY"]
SECRET = os.environ["MEKTUP_WEBHOOK_SECRET"].encode()

@app.post("/inbound")
async def inbound(request: Request, tasks: BackgroundTasks):
    raw = await request.body()
    expected = hmac.new(SECRET, raw, hashlib.sha256).hexdigest()
    got = request.headers.get("x-mektup-signature", "").removeprefix("sha256=")
    if not hmac.compare_digest(expected, got):
        raise HTTPException(401)
    tasks.add_task(handle, json.loads(raw))  # answer Mektup at once
    return {"ok": True}

def handle(event):
    msg = event["message"]
    # the whole conversation, oldest first
    thread = requests.get(f"{API}/threads/{requests.utils.quote(msg['threadKey'], safe='')}",
                          params={"mailbox": event["mailbox"]},
                          headers={"Authorization": f"Bearer {KEY}"}).json()["messages"]
    answer = my_model(thread, msg)  # your LLM call
    requests.post(f"{API}/emails", headers={"Authorization": f"Bearer {KEY}"}, json={
        "from": event["mailbox"], "to": msg["from"],
        "subject": "Re: " + (msg["subject"] or ""), "text": answer,
        "inReplyTo": msg["id"],  # same thread for the customer and in Mektup
    })

The handler answers Mektup at once and works in the background: the webhook times out after 8 seconds and is not retried. The message is stored either way, so a scheduled GET /v1/messages catches anything missed.

3. Let people see it

Open ada@agents.yourcompany.com in Mektup's webmail, or add it to a mail app with its IMAP and SMTP login. You see what came in and everything the agent sent, and can answer yourself. To make the agent ask first, create drafts instead of sending: the shared inbox.

4. Or skip the code with MCP

In Claude Code, Cursor or another MCP client, connect https://mcp.usemektup.com/mcp and ask the agent to set up its own mailbox: it calls create_domain, create_mailbox and set_mailbox_webhook itself. MCP setup.