MepMail

@mepmail/mcp

Official MepMail MCP server for local MCP clients — Claude Desktop, Claude Code, Cursor, Codex and anything that speaks stdio. It drives your MepMail instance over the public REST API (Resend-compatible wire) with a team API key, and, with a Correio agent key, your mailboxes: read the inbox, save replies as drafts and send them (or ask the owner to approve).

MepMail also runs a hosted MCP server (OAuth, no install) at https://api.mepmail.dev/mcp. This package is for clients that launch local servers from config. Tool names and result shapes match the hosted server's; it covers a subset — the reading, sending and contact tools (22) — and the write surfaces beyond contacts (segments, topics, broadcasts, templates, webhooks, domains, API keys) plus the team picker are hosted-only.

Guide: https://docs.mepmail.dev/mcp · Packages: https://docs.mepmail.dev/packages · Published as @mepmail/mcp on npm.

Requires Node.js 20 or newer.

Quickstart

1. Create an API key in the MepMail dashboard (API keys) — a full-access key, optionally scoped to the sender domain your agent sends from. A sending-access key is confined to /emails, so it would 403 on the contact tools (list_contacts, get_contact, create_contact, update_contact, delete_contact) with restricted_api_key.
2. Add the server to your client:

Claude Desktop (claude_desktop_config.json) — and any client with the same config shape (Cursor: mcp.json):

{
  "mcpServers": {
    "mepmail": {
      "command": "npx",
      "args": ["-y", "@mepmail/mcp"],
      "env": {
        "MEPMAIL_API_KEY": "ms_...",
        "MEPMAIL_BASE_URL": "https://api.mepmail.dev"
      }
    }
  }
}

Claude Code:

claude mcp add mepmail -e MEPMAIL_API_KEY=ms_... -e MEPMAIL_BASE_URL=https://api.mepmail.dev -- npx -y @mepmail/mcp

Correio mailboxes — create an agent key in Correio → Settings → Agents: mmb_... for one mailbox, or "Connect an agent to several mailboxes" for an mmt_... credential over the mailboxes you choose, with read, draft and optionally send permission. Then add it to the same server (an API key is optional when you only need mailboxes):

claude mcp add mepmail -e MEPMAIL_MAIL_TOKEN=mmt_... -- npx -y @mepmail/mcp

Environment

Set at least one of MEPMAIL_API_KEY and MEPMAIL_MAIL_TOKEN.

Variable	Required	Default	Meaning
MEPMAIL_API_KEY	for sending tools	—	Team API key (ms_...). Sent as Bearer to your instance only.
MEPMAIL_BASE_URL	no	https://api.mepmail.dev	Your instance's API URL.
MEPMAIL_MAIL_TOKEN	for mailbox tools	—	Correio agent key (mmb_... or mmt_...). Sent as Bearer to the dashboard origin only.
MEPMAIL_MAIL_ORIGIN	no	https://mepmail.dev	Where your dashboard answers.

Tools (22)

Send and manage email:

• send_email — send or schedule one transactional email (cc/bcc/reply_to, tags, attachments, topic-scoped sends).
• send_email_batch — up to 100 emails in one call.
• get_email, list_emails — status and timeline (last_event: delivered, bounced, complained, ...).
• update_email, cancel_email — reschedule or cancel a scheduled email.
• get_email_insights — per-email best-practice report and score.
• get_deliverability, get_usage — account standing before bulk work.

Audience and account:

• create_contact, update_contact, delete_contact (with erase=true for GDPR/LGPD scrubbing), get_contact, list_contacts — with segment filters.
• list_domains, get_domain — DNS records and verification state.
• list_broadcasts, get_broadcast.
• list_templates, get_template.
• list_webhooks, list_suppressions.

Correio mailboxes (with MEPMAIL_MAIL_TOKEN, same five tools as the hosted https://api.mepmail.dev/mcp/correio):

• mailbox_list_accounts — the mailboxes the key reaches, with permissions and the default one.
• mailbox_list_messages, mailbox_read_message — inbox, drafts and sent; pass mailbox with a team credential. Listing is one page at a time, newest first: pass the returned nextCursor as cursor until hasMore is false (a cursor only works for the same mailbox, folder and filters). Filters run on the server before the page is cut: query (words, "quoted phrases", de:/from:, para:/to:, assunto:/subject:, tem:anexo, depois:/antes:), from, subject, unread, after, before; limit up to 100 (50 when searching). Mail that arrives while paging comes before the first page, so start over to see it. A short or empty page never proves a message is absent from the mailbox, and search reads an index that can lag about a minute behind new mail. Dates: a listing's after/before use the order time (arrival, or when a snoozed message came back; a draft's last edit), a search uses the arrival time, and a search also finds snoozed messages, which the listing leaves out until they return.
• mailbox_get_attachment — one attachment by message id, revision and index (from mailbox_read_message): filename, bytes and sha256. With MEPMAIL_MAIL_DOWNLOAD_DIR set the file is saved there (never overwriting); otherwise it comes back as content_base64, up to 512 KiB.
• mailbox_save_draft — new draft, edit, reply or forward, from that mailbox's address and signature. attachments adds files as { filename, content_base64 }, or { path } for a file inside MEPMAIL_MAIL_UPLOAD_DIR (no other local path is ever read); keep_attachments picks the files to keep from the edited draft or the forwarded message (by default all of them; a reply keeps none). Limits: 10 files, 256 KiB each, about 700 KiB in all. Files travel only inside the draft request, so nothing is left behind when a draft is abandoned.
• mailbox_send_draft — sends with the send permission; otherwise the owner gets an approval request (awaiting_approval).

Every tool result is one JSON block envelope — { notice, untrusted_data } — so agents can tell team-authored strings from tool output and never treat recipient data as instructions.

Safe retries when sending

send_email and send_email_batch accept an optional top-level idempotency_key. Keep the same key and identical arguments when retrying the same send operation. Generate a new key for a new operation. The server passes it as the HTTP Idempotency-Key header; it is not an email header or message field.

Keys are scoped to the team and retained for 24 hours. A completed retry replays the original result. Reusing a key with different arguments returns a conflict; an operation still in progress can also return a conflict. An incomplete reservation can be recovered after 10 minutes. These limits apply to the server, so use an API version that supports this contract.

Agent discovery

• Machine catalog: https://mepmail.dev/.well-known/ai-catalog.json
• Auth guide for agents: https://mepmail.dev/auth.md
• API + errors + rate limits: https://docs.mepmail.dev

License

MIT