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Lettio MCP

Registre officiel Recherche et web

Private, EU-hosted email for AI agents over JMAP: read, search, reply, organize, send.

Code source Documentation

Installation

Ajoutez ceci à la configuration MCP de votre client (Claude Desktop : claude_desktop_config.json ; Cursor : .cursor/mcp.json ; VS Code et les autres utilisent la même forme « mcpServers »).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http lettio-mcp 'https://mcp.lettio.eu/mcp'
Configuration JSON (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "lettio-mcp": {
            "type": "http",
            "url": "https://mcp.lettio.eu/mcp"
        }
    }
}
NPM package @lettio/mcp
Claude Code 
claude mcp add lettio-mcp -e 'LETTIO_USERNAME=<LETTIO_USERNAME>' -e 'LETTIO_PASSWORD=<your lettio_password>' -e 'LETTIO_HOST=<LETTIO_HOST>' -- npx -y @lettio/mcp@0.1.2
Configuration JSON (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "lettio-mcp": {
            "command": "npx",
            "args": [
                "-y",
                "@lettio/mcp@0.1.2"
            ],
            "env": {
                "LETTIO_USERNAME": "<LETTIO_USERNAME>",
                "LETTIO_PASSWORD": "<your lettio_password>",
                "LETTIO_HOST": "<LETTIO_HOST>"
            }
        }
    }
}

Variables d'environnement

  • LETTIO_USERNAME obligatoire Full email address of the Lettio mailbox, e.g. you@yourcompany.eu.
  • LETTIO_PASSWORD obligatoire secret App password for the mailbox.
  • LETTIO_HOST Mail host. Defaults to https://mail.lettio.eu.

Documentation

Tirée du README du projet sur GitHub, actualisée chaque semaine. Les liens ouvrent GitHub.

Sommaire
  1. Lettio MCP
  2. Tools
  3. Requirements
  4. Use with Claude Desktop
  5. Configuration
  6. Security
  7. Run from source
  8. License

Lettio MCP

Let your AI assistant read, search and send email from a private, EU-hosted mailbox.

Lettio MCP is a Model Context Protocol server that connects an AI agent (Claude, Cursor, and any other MCP client) to a Lettio mailbox over JMAP. Your assistant can triage your inbox, find a message, and send a reply — without your email ever leaving Europe.

  • 🇪🇺 European by default — talks to your own EU-hosted mailbox, no third‑party middleman.
  • 🔒 Safe sending — the server can only ever send as the mailbox it is signed in to. It cannot be tricked into sending from another address.
  • 📬 Everything an agent needs — list, search, read and send, over the open JMAP standard.
  • 👥 One or many mailboxes — configure a single account or several.

Prefer nothing to install? Lettio also runs as a hosted, OAuth‑secured MCP server at https://mcp.lettio.eu/mcp — add that URL in your client and sign in. This npm package is the local / self‑hosted option for people who want to run it on their own machine.

Tools

ToolWhat it does
list_accountsList the mailboxes this server is configured for.
list_mailboxesList folders in an account, with message and unread counts.
list_recent_emailsMost recent messages in a mailbox (defaults to the inbox).
search_emailsFree‑text search across sender, subject and body.
read_emailFull content of one message by id.
send_emailSend a plain‑text email as the signed‑in mailbox.
reply_emailReply in‑thread (keeps the conversation), optionally reply‑all.
set_read_statusMark a message read or unread.
flag_emailFlag (star) or unflag a message.
move_emailMove to a folder — archive, trash (reversible), or a folder name.

Requirements

  • Node.js 18 or newer.
  • A Lettio mailbox and an app password for it (use a dedicated app password, not your main login).

Use with Claude Desktop

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "lettio": {
      "command": "npx",
      "args": ["-y", "@lettio/mcp"],
      "env": {
        "LETTIO_USERNAME": "you@yourcompany.eu",
        "LETTIO_PASSWORD": "your-app-password"
      }
    }
  }
}

Restart Claude Desktop; the Lettio tools appear in the tools menu.

Configuration

Configured entirely through environment variables.

Single mailbox
VariableRequiredDescription
LETTIO_USERNAMEyesFull email address, e.g. you@yourcompany.eu.
LETTIO_PASSWORDyesMailbox app password.
LETTIO_HOSTnoMail host. Defaults to https://mail.lettio.eu.
LETTIO_ACCOUNT_NAMEnoFriendly name for the account (default: the username).
Several mailboxes

Set LETTIO_ACCOUNTS to a JSON array and omit the single‑account variables:

[
  { "name": "work", "username": "you@yourcompany.eu", "password": "app-password" },
  { "name": "sales", "username": "sales@yourcompany.eu", "password": "app-password" }
]

Then pass account: "work" to any tool to choose which mailbox to use.

Security

Sending is deliberately constrained. Before it sends, the server asks the mail host for the identities the signed‑in mailbox is allowed to use and requires one that matches the login address. The From header and the SMTP envelope MAIL FROM are both pinned to that address. There is no parameter for choosing a different sender, so an agent can never send "from" a foreign or arbitrary mailbox. Credentials are read from the environment, kept only in memory, and never logged.

Run from source

npm install
npm run build
LETTIO_USERNAME=you@yourcompany.eu LETTIO_PASSWORD=app-password npm start

License

MIT © Valmia Solutions s.r.o.

Questions fréquentes

Qu'est-ce que Lettio MCP ?

Private, EU-hosted email for AI agents over JMAP: read, search, reply, organize, send.

Comment installer Lettio MCP ?

Il fonctionne comme serveur distant. Dans Claude Code : claude mcp add --transport http lettio-mcp 'https://mcp.lettio.eu/mcp'. Pour les autres clients, collez la configuration JSON de cette page dans leurs réglages MCP.

Faut-il une clé API pour Lettio MCP ?

Oui. Il attend LETTIO_USERNAME, LETTIO_PASSWORD, à renseigner dans sa configuration.

Lettio MCP est-il open source ?

Oui. Son code est sur GitHub sous licence MIT.

Qui maintient Lettio MCP ?

Il est publié par lettio-eu. AI.tn le référence sans le maintenir ni le recommander.

Issu du registre MCP officiel. Être listé n'est pas une recommandation : vérifiez le code et les permissions d'un serveur avant de lui donner accès à vos données.