MCP Protocol Overview

What is the MCP Protocol?

The Model Context Protocol (MCP) is an open standard for communication between AI clients (Claude, Cursor, Windsurf) and tool servers. GetMCP implements the MCP specification using the Streamable HTTP transport.

Endpoint

Each GetMCP server exposes a single HTTP endpoint:

https://yoursite.com/mcp/{slug}

URL Part	Description
`{slug}`	The server’s URL slug (e.g., `my-weather-tools`)

Transport: Streamable HTTP

All MCP requests use the Streamable HTTP transport:

Method	Purpose
`POST`	Send JSON-RPC requests (the primary method)
`GET`	Open an SSE stream for server-initiated messages
`DELETE`	Terminate a session
`OPTIONS`	CORS preflight

Headers

Required for POST requests:

Content-Type: application/json

Optional session tracking:

Mcp-Session-Id: {session_id}

If Mcp-Session-Id is not provided, a new session ID is generated and returned in the response. Authentication (if server requires it):

Authorization: Bearer {api_key}

JSON-RPC 2.0

All POST request bodies and responses follow the JSON-RPC 2.0 specification.

Request Format

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_weather",
    "arguments": {
      "city": "London"
    }
  }
}

Response Format

Success:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "content": [
      {"type": "text", "text": "..."}
    ]
  }
}

Error:

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32601,
    "message": "Method not found: unknown/method"
  }
}

Batch Requests

GetMCP supports JSON-RPC batch requests — send an array of request objects and receive an array of responses:

[
  {"jsonrpc": "2.0", "id": 1, "method": "ping", "params": {}},
  {"jsonrpc": "2.0", "id": 2, "method": "tools/list", "params": {}}
]

Notifications

Requests without an id field are notifications. GetMCP processes them but returns no response (HTTP 202).

{
  "jsonrpc": "2.0",
  "method": "notifications/initialized",
  "params": {}
}

Supported Methods

Method	Description
`initialize`	Negotiate protocol version and get server capabilities
`ping`	Check server connectivity
`tools/list`	List all available tools
`tools/call`	Execute a specific tool
`resources/list`	List all available resources
`resources/read`	Read the content of a resource by URI
`prompts/list`	List all available prompt templates
`prompts/get`	Retrieve a rendered prompt with argument values substituted

Error Codes

Code	Description
`-32700`	Parse error — invalid JSON
`-32600`	Invalid request — malformed JSON-RPC structure
`-32601`	Method not found
`-32602`	Invalid params
`-32603`	Internal error — server-side exception

Overview

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MCP Protocol

MCP Protocol Overview

What is the MCP Protocol?

Endpoint

Transport: Streamable HTTP

Headers

JSON-RPC 2.0

Request Format

Response Format

Batch Requests

Notifications

Supported Methods

Error Codes

​What is the MCP Protocol?

​Endpoint

​Transport: Streamable HTTP

​Headers

​JSON-RPC 2.0

​Request Format

​Response Format

​Batch Requests

​Notifications

​Supported Methods

​Error Codes

What is the MCP Protocol?

Endpoint

Transport: Streamable HTTP

Headers

JSON-RPC 2.0

Request Format

Response Format

Batch Requests

Notifications

Supported Methods

Error Codes