📬 XTND | MCP | ONE

The Premier Model Context Protocol (MCP) Server for one.com Mail Infrastructure

Empower Claude, Cursor, ChatGPT, Zed, and autonomous AI agents with full mailbox intelligence (IMAP/SMTP) over one.com.

Features • Client Setup Guides • Tool Catalog • Workflow Prompts • Dynamic Resources • Architecture • Security

🚀 Key Features

• 📂 Complete Mailbox Hierarchy: Manage all standard and custom folders (INBOX, Drafts, Sent, Archive, Trash) with real-time total and unread message counters.

• 🔍 Server-Side Search Engine: Search by full-text keyword, sender, recipient, subject, date ranges, and flags (unread, flagged) without downloading gigabytes of data.

• 📖 AI Context Protection: Automatically converts HTML emails into clean, token-efficient Markdown, stripping tracking pixels, inline CSS blobs, and scripts.

• 🏷️ Triage & Flagging: Mark emails as read/unread/flagged, batch move between folders, and perform safe trash or permanent expunge.

• ✉️ Outbound SMTP Delivery: Send new messages via send.one.com:465 (implicit TLS), draft intelligent replies with automated In-Reply-To/References, forward threads, and manage drafts.

• ⚡ Triple-Transport Architecture:

  1. NPX Stdio for local desktop clients (npx @xtnd-dynamics/mcp-one).

  2. Streamable HTTP (/mcp) for Smithery, Cursor, and web AI agents.

  3. Server-Sent Events (/sse) for legacy streaming clients.

Related MCP server: Mailbridge MCP

📦 Client Setup Guides

1. Claude Desktop (Local NPX)

Add the following to your claude_desktop_config.json:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "XTND | MCP | ONE": {
      "command": "npx",
      "args": ["-y", "@xtnd-dynamics/mcp-one"],
      "env": {
        "ONECOM_EMAIL": "user@yourdomain.com",
        "ONECOM_PASSWORD": "your_mailbox_password"
      }
    }
  }
}

2. 1-Click Install via Smithery CLI

npx -y @smithery/cli install @xtnd-dynamics/mcp-one --client claude

3. Cursor IDE (.cursor/mcp.json)

{
  "mcpServers": {
    "one-mail": {
      "command": "npx",
      "args": ["-y", "@xtnd-dynamics/mcp-one"],
      "env": {
        "ONECOM_EMAIL": "user@yourdomain.com",
        "ONECOM_PASSWORD": "your_mailbox_password"
      }
    }
  }
}

4. Zed Editor (settings.json)

{
  "context_servers": {
    "one-mail": {
      "command": {
        "path": "npx",
        "args": ["-y", "@xtnd-dynamics/mcp-one"],
        "env": {
          "ONECOM_EMAIL": "user@yourdomain.com",
          "ONECOM_PASSWORD": "your_mailbox_password"
        }
      }
    }
  }
}

5. Remote Hosted Edge Gateway (Streamable HTTP / SSE)

For web-based AI clients or SaaS deployments:

• Streamable HTTP Endpoint: https://one.mcp.xgi.io/mcp

• SSE Endpoint: https://one.mcp.xgi.io/sse

{
  "mcpServers": {
    "XTND | MCP | ONE": {
      "url": "https://one.mcp.xgi.io/mcp",
      "headers": {
        "X-OneCom-Email": "user@yourdomain.com",
        "X-OneCom-Password": "your_mailbox_password"
      }
    }
  }
}

🛠️ Tool Catalog (15 Tools)

🧠 Workflow Prompts (4 Assistants)

📂 MCP Resources (4 Endpoints)

🏛️ Architecture

flowchart TD
    subgraph Clients ["AI Clients & Platforms"]
        CD["Claude Desktop"]
        CR["Cursor / Zed / Windsurf"]
        CG["ChatGPT Custom GPTs"]
        SM["Smithery Marketplace"]
    end

    subgraph LocalTransport ["Local Execution"]
        NPX["npx @xtnd-dynamics/mcp-one\n(Stdio Protocol)"]
    end

    subgraph EdgeTransport ["Cloudflare Edge (one.mcp.xgi.io)"]
        HTTP["Streamable HTTP (/mcp)"]
        SSE["Server-Sent Events (/sse)"]
        CARD["Static Server Card (/.well-known/mcp/server-card.json)"]
    end

    subgraph CoreEngine ["XTND Core Engine"]
        MIME["MIME & Markdown Token Optimizer"]
        IMAP["IMAP Client (imap.one.com:993 TLS)"]
        SMTP["SMTP Client (send.one.com:465 TLS)"]
    end

    subgraph OneCom ["One.com Mail Infrastructure"]
        MBOX["User Mailboxes & Folders"]
        MX["Mail Submission Relays"]
    end

    CD --> NPX
    CR --> NPX
    CR --> HTTP
    SM --> HTTP
    CG --> HTTP
    CD --> SSE

    NPX --> MIME
    HTTP --> MIME
    SSE --> MIME

    MIME --> IMAP
    MIME --> SMTP

    IMAP <--> MBOX
    SMTP --> MX

🔒 Security & AI Token Budgeting

• Zero-Credential Storage: Credentials are never persisted on edge servers. Stdio uses local process environment; hosted gateway uses ephemeral request headers.

• Implicit TLS Only: Inbound connections use port 993 (IMAPS) and outbound uses port 465 (SMTPS) over strict TLS sockets, avoiding STARTTLS vulnerabilities.

• Token Budget Guard: Incoming HTML is sanitized and converted to semantic Markdown, discarding CSS boilerplate, tracking pixels, and binary attachments to prevent context window exhaustion.

📄 License

MIT License © 2026 XTND Dynamics. Developed for the global AI developer ecosystem.