MCP Transport Prototype

🚀 mcp-transport-prototype

A prototype implementation for understanding how to build a custom MCP server accessible via stdio and SSE transport protocols. The goal of this project is to understand SSE and stdio transport protocols.

🚀 Quick Start

SSE Transport Protocol

Server-Sent Events (SSE) is a simple and efficient way to push real-time updates from the server to the client over HTTP.

• Unlike WebSocket, SSE is unidirectional: the server can push data to the client, but the client cannot send data back.
• It runs on standard HTTP and is well-suited for scenarios that require real-time updates, notifications, or streaming responses.

Compared to stdio, SSE runs the MCP server as a separate HTTP service. This makes it ideal for web dashboards or browser-based applications that need to receive real-time updates over the network from the server.

Stdio Transport Protocol

Stdio (Standard Input Output) is a traditional way of communication between programs, achieved by reading standard input (stdin) from the terminal, files, or other programs, and sending standard output (stdout) to the terminal, files, or other programs.

• stdin (Standard Input): Receives input data — usually from the keyboard, a file, or another program.
• stdout (Standard Output): Sends output data — usually displayed on the terminal or passed to another program through a pipeline.

Compared to SSE, the Stdio-based MCP server is more like an internal tool. They are well-suited for starting the MCP server as a subprocess, for example, from a command-line tool, a large language model (LLM) agent, or a background script that needs to efficiently send and receive structured data without using the network.

💻 Usage Examples

Basic Usage

mcp_client.py is a simple script for testing the MCP server in SSE mode.

# Run in terminal 1
uv run main.py

# Run in terminal 2
uv run mcp_client.py