MCP Server Connection Types

MCP supports multiple connection types that define how clients communicate with servers. This section focuses on the two most common protocols:

STDIO — for local, lightweight server execution
SSE (Server-Sent Events) — for remote, web-hosted servers

MCP Connection Types

An MCP connection type defines how the client opens a communication channel with the server. Clients must use one of the supported protocols to start a session, send tool requests, and receive results.

Type	Transport	Example Use
`STDIO`	Standard Input/Output	Run server from local script file
`SSE`	Server-Sent Events over HTTP	Connect to hosted API endpoint

STDIO: Local Execution

Launches a script file locally (.py, .js)
Communicates via system I/O streams
No internet required

Required Config Fields

Field	Description	Example
`command`	What to run	`python`, `node`
`args`	Script and arguments	`[index.js]`
`env`	Environment vars (optional)	`{ UV_PATH: "/path/to/uv" }`

"server": {
  "type": "stdio",
  "command": "node",
  "args": ["dist/index.js"],
  "env": {
    "UV_PATH": "/Users/you/.cargo/bin/uv"
  }
}

SSE: Remote Access via HTTP

Sends requests to a hosted API server
Listens to streaming responses over HTTP
Ideal for production deployment

Required Config Fields

Field	Description	Example
`type`	Must be `sse`	`"sse"`
`url`	Endpoint for receiving events	`https://yourdomain.com/api/mcp`
`headers`	Optional auth headers	`{ Authorization: "Bearer xxx" }`

"server": {
  "type": "sse",
  "url": "https://api.example.com/mcp-server",
  "headers": {
    "Authorization": "Bearer your-token"
  }
}

MCP Client User Guide OMS Overview