Simple Stateless Model Context Protocol

🚧 WORK IN PROGRESS, ONLY TOOLS, RESOURCES AND PROMPTS SUPPORTED 🚧

SSMCP is a stateless model context protocol that is designed to be easy to understand and implement for web developers. It is built on top of HTTP and tries to follow common HTTP conventions like REST and HATEOAS. All SSMCP servers can be used as MCP servers through an adapter script npx ssmcp --url http://127.0.0.1/.

Why?

Because most MCP servers do not use nor require the stateful features of the protocol and by removing them the complexity can be drastically reduced.

Overview

SSMCP services are discovered by a GET request to the root URL. Thereafter the root URL is used as a base to derive other URLs.

GET /

Returns the server manifest which contains information and capabilities. Analogous to InitializeResult in the MCP Specification.

Response Body

{
  "name": "calculator",
  "version": "1.0.0",
  "tools": true
}

GET /tools

Lists tools provided by the server. Analogous to ListToolsResult in the MCP Specification. Unlike MCP there is no pagination.

Response Body

[
  {
    "name": "add",
    "description": "Add two numbers",
    "inputSchema": {
      "type": "object",
      "properties": {
        "a": {
          "type": "number"
        },
        "b": {
          "type": "number"
        }
      },
      "required": ["a", "b"]
    }
  }
]

POST /tools/:name

Tool call, the URL parameter name corresponds to the tool name listed in GET /tools and the json body matches the inputSchema JSON Schema.

Request Body

{
  "a": 13,
  "b": 29
}

The Content-Type of the response matters because the ssmcp adapter uses it to control how the content is converted to MCP content. For example text/plain is converted to TextContent.

Response

HTTP/1.1 200 Ok
Content-Type: text/plain

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