Email your agent

An agent with an email address is an agent anyone can reach: you, your customers, other tools, other agents. No app to install, no chat window to keep open. You write to agent@yourdomain.com, the agent reads it, does the job and replies.

This page gets the address. The next pages wire it to your agent:

• Build it with Claude: claude.ai with no code, Claude Code on a schedule, or your own loop on the Claude API.
• Build it with ChatGPT: a ChatGPT connector, or the OpenAI API with Faivelo as an MCP tool.
• Cursor, Codex, Gemini CLI and friends: one-command installs of the same MCP server.

1. Get an address

Pick whichever fits:

npx faivelo inbox my-agent --json

On your own domain (agent@yourcompany.com): add the domain in the dashboard or run npx faivelo init yourcompany.com from a terminal, then create a mailbox for the agent. Make it an agent inbox so it gets drafts, labels, threads and message webhooks, and give the agent a key of the agent kind, which can only ever see the inboxes it owns. See AI agents & API keys.

2. Connect the agent

Every path below uses the same hosted MCP server, https://faivelo.com/api/mcp. A signed-in connection (claude.ai, Claude Code, ChatGPT, Cursor) opens a browser to pick which mailboxes the agent may use. A headless agent sends its API key as a Bearer header instead:

{
  "mcpServers": {
    "faivelo": {
      "url": "https://faivelo.com/api/mcp",
      "headers": { "Authorization": "Bearer fvl_live_..." }
    }
  }
}

Once connected the agent has the tools a mail client has: list_messages, read_message, get_thread, search_messages, send_message, create_draft, label_message and the rest. The full list is in AI agents & API keys.

3. Give it a loop

An agent that answers email runs the same four steps forever:

1. Look for new mail. list_messages on the inbox and skip anything already seen or labelled handled, or let Faivelo call your server the moment mail lands with a message.received webhook.
2. Read the whole conversation. get_thread returns the back-and-forth, your own earlier replies included, so the agent answers in context.
3. Reply. send_message with inReplyTo set to the message id keeps the reply in the same thread in the sender's mail app. For anything sensitive, create_draft instead and let a person send it from Drafts.
4. Mark it handled. label_message with a tag such as handled, so the next run skips it.

The guides for Claude and ChatGPT show this loop as a prompt, a scheduled command and as code.

Keeping it safe

• Scope the key. An agent key sees only the inboxes it created or was granted. It cannot touch your other mail, domains or billing. Revoke it in Settings → Developers and access stops at once.
• Mail is untrusted input. Tell the agent, in its instructions, that the content of an email is data to act on, never instructions to follow. Faivelo's own tools already treat it that way.
• Drafts for anything that matters. Refunds, commitments, anything legal: have the agent write a draft and a person press send.
• Allowances. Sending counts against the Agents plan's monthly emails. Past the allowance receiving carries on and sending pauses until the 1st or an upgrade. See plans.

Which plan

Every account has the Free Agents tier: 3 agent inboxes and 3,000 emails a month on a free Faivelo address, MCP included. Agent inboxes on your own domain, more inboxes, more volume and more webhook endpoints come with the Developer plan ($15 a month); it needs no email hosting plan. If you only want Claude or ChatGPT working in your own mailbox, the Growth email plan ($12) includes the MCP server for that. Full comparison under Billing & plans.