> ## Documentation Index
> Fetch the complete documentation index at: https://docs.paubox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MCP Server quickstart

> Connect the Paubox MCP Server to Claude, Claude Desktop, Claude Code, or any MCP-compatible client.

<Warning>
  **HIPAA Notice:** If you plan to send or reference PHI when using the Paubox MCP connector through Claude, you must have a Business Associate Agreement (BAA) in place with Anthropic. BAAs are available on Claude Team and Enterprise plans. Your Paubox subscription covers email delivery, it does not cover protected health information (PHI) processed within Claude's context window.
</Warning>

<Steps>
  <Step title="Get your API key">
    Before connecting, you need a Paubox Email API key. See [Authentication](/mcp-server/authentication) for how to generate one from the Paubox dashboard.
  </Step>

  <Step title="Connect via Claude.ai">
    1. In [Claude.ai](https://claude.ai), open **Settings > Integrations**.
    2. Click **Add connector** and enter the server URL:

    ```
    https://mcp.paubox.com
    ```

    3. A **Configure Paubox** form opens automatically. Enter your API key.
    4. Click **Save**. Claude stores your API key as a secure token and sends it on every request.

    Claude will discover the available Paubox tools automatically.
  </Step>

  <Step title="Connect via Claude Desktop">
    Open (or create) `claude_desktop_config.json` and add the `paubox` entry to `mcpServers`:

    <CodeGroup>
      ```json claude_desktop_config.json (HTTP, recommended) theme={null}
      {
        "mcpServers": {
          "paubox": {
            "url": "https://mcp.paubox.com"
          }
        }
      }
      ```

      ```json claude_desktop_config.json (stdio) theme={null}
      {
        "mcpServers": {
          "paubox": {
            "command": "npx",
            "args": ["-y", "@paubox/mcp@latest"],
            "env": {
              "PAUBOX_API_KEY": "YOUR_API_KEY"
            }
          }
        }
      }
      ```
    </CodeGroup>

    The config file is located at:

    * **macOS**: `~/Library/Application Support/Claude/claude_desktop_config.json`
    * **Windows**: `%APPDATA%\Claude\claude_desktop_config.json`

    When using the HTTP config, Claude Desktop will open a browser window to the Configure Paubox form to collect your credentials. Restart Claude Desktop after saving.
  </Step>

  <Step title="Connect via Claude Code">
    Run this command once with your API key (no credential prompts afterward):

    ```bash theme={null}
    claude mcp add paubox \
      -e PAUBOX_API_KEY=your_api_key \
      -- npx @paubox/mcp@latest
    ```

    Claude Code spawns the package locally and injects the API key as an environment variable.
  </Step>

  <Step title="Test the connection">
    Ask Claude to verify your credentials:

    > "Use the Paubox MCP server to validate my credentials."

    Claude will call `validate_credentials` and confirm your API key is working. Then try sending a test email:

    > "Send a test email to [me@example.com](mailto:me@example.com) from [sender@yourdomain.com](mailto:sender@yourdomain.com) with the subject 'Hello from MCP'."

    Claude will call `send_secure_email` and return a `sourceTrackingId` you can use to check delivery status.
  </Step>
</Steps>

## Other MCP-compatible clients

Any client that supports the MCP specification can connect using either transport:

* **HTTP**: `https://mcp.paubox.com`; use OAuth (credential form in the client UI) or set `x-paubox-api-key` as a custom request header
* **stdio**: run `npx @paubox/mcp@latest` with `PAUBOX_API_KEY` set in the environment


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