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Documentation MCP Server

https://mcp.emailengine.app is a public MCP server that gives an AI client read-only access to the EmailEngine documentation, the REST API reference and the EmailEngine source code. Connect it to Claude, Cursor or any other MCP client, and the agent can look up exact settings, environment variables, defaults and API fields while it helps you install, configure or troubleshoot an instance.

This is a different server from the MCP endpoint every EmailEngine instance serves:

Documentation serverYour instance's MCP endpoint
Addresshttps://mcp.emailengine.apphttps://your-instance/mcp
Run byPostal SystemsYou, as part of EmailEngine
ReachesPublic documentation, API reference and source codeThe mailboxes and settings of your instance
AuthenticationNoneAn EmailEngine access token or OAuth sign-in
Can change anythingNo, every tool is read-onlyYes, depending on the token's access level

The documentation server never connects to your instance and cannot see your accounts, settings, tokens or licence. Connect both when you want an agent that can read the docs and act on your instance.

Connect a client​

The server needs no account, token or API key.

Claude Code:

claude mcp add --transport http emailengine-docs https://mcp.emailengine.app

claude.ai and Claude Desktop: add a custom connector with the name "EmailEngine docs" and the remote MCP server URL https://mcp.emailengine.app. Leave the OAuth client fields empty.

JSON configuration (Cursor, project-level .mcp.json files and most clients configured through a file):

{
  "mcpServers": {
    "emailengine-docs": {
      "type": "http",
      "url": "https://mcp.emailengine.app"
    }
  }
}

Any client that speaks Streamable HTTP works the same way. Opening the address in a browser redirects to this documentation site.

Tools​

All five tools are read-only lookups and are annotated with readOnlyHint.

ToolArgumentsReturns
search_docsquery (string)Up to six matching sections of the documentation, the API reference, the emailengine.app pages and the account, licence and support notes, each with its title, section heading, link and an excerpt of up to 1,500 characters
read_pageurl (string)One whole page by a URL that search_docs returned, up to 15,000 characters. Any #fragment is ignored
get_api_operationmethod (GET, POST, PUT, PATCH or DELETE), path (string)Parameters, request body fields and response fields of one REST operation, for example POST /v1/account/{account}/submit. An unknown path returns the names of similar operations
search_codeterms (string), path_prefix (string, optional)Lines of the EmailEngine source that contain all the given terms, case-insensitive, with file and line number. At most six terms and 30 lines are used, and the result names the release it searched
read_sourcepath (string), start_line (integer), end_line (integer)Up to 300 numbered lines of one source file, by a path that search_code returned

search_docs works best with several short keyword queries, such as webhook signature serviceSecret, rather than one long sentence. search_code is the way to find environment variables (EENGINE_*), setting names and defaults that the documentation does not state.

The server also returns short usage instructions in its initialize response, describing which tool to use for what.

What the server knows​

  • The pages of this documentation site, from its sitemap
  • The REST API reference, from the OpenAPI spec of the latest EmailEngine release
  • The source code of the latest EmailEngine release
  • The public pages of emailengine.app

The index is rebuilt every six hours, so it can lag a documentation change or a new release by that long. The source code and the API reference always describe the latest release. If your instance runs an older version, tell the agent which version you have, and check behavior that changed between releases in the changelog.

Example​

With both servers connected, a request like the following lets the agent combine them:

Send new-message webhooks from my EmailEngine instance to https://example.com/webhooks.

The agent searches the documentation server for webhook configuration and finds the settings involved: webhooksEnabled, webhooks and webhookEvents. It then calls update_settings on your instance's MCP endpoint, which needs a token with the Operate management level or higher. EmailEngine tells management agents to confirm with you before changing where webhooks are delivered. Without the instance endpoint connected, the agent explains the settings and leaves the change to you.

Limits​

  • Each IP address can make 600 requests per hour, and each /24 IPv4 range or /64 IPv6 range 1,800. A request over the limit receives HTTP 429 with a JSON-RPC error.
  • The server is stateless. It does not open a server-to-client event stream, so GET requests with Accept: text/event-stream receive 405.
  • Requests that carry a browser Origin header from a site other than this documentation site are refused, so a web page cannot call the server from a visitor's browser.
  • It implements the initialize, ping, tools/list and tools/call methods. It has no resources or prompts.
  • Supported protocol versions: 2025-11-25, 2025-06-18, 2025-03-26 and 2024-11-05.

Privacy​

The server stores how many times each tool was called per day. It does not store the queries, the tool arguments or the results. Tool calls do not pass through any language model on the Postal Systems side: the model that reads the results is the one in your client.

See Also​