MCP SSE demo

demo of MCP SSE server limitations using the bun runtime

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Overview

MCP SSE Demo is a reproducible demonstration that showcases the limitations of an MCP SSE server when using the Bun runtime compared to Node.js.

To use MCP SSE Demo, follow these steps:

Install dependencies using Bun: bun install.
Run the MCP inspector with npm run inspect.
Open the inspector at http://localhost:5173.
Select SSE as the transport and enter http://localhost:3500/sse as the URL.
Open the dev tools network tab to inspect traffic.
In another terminal, run the server using Bun: npm run start:bun.
Connect to the server using the inspector and observe the logs.
Kill the Bun server and run the server using Node.js: npm run start:node.
Connect again to see the successful SSE connection.

Demonstrates server behavior with different runtimes (Bun vs Node.js). - Provides a visual inspector for monitoring SSE connections. - Allows users to observe network traffic and logs during the connection process.

Testing server performance with different runtimes.
Educational purposes for understanding SSE connections.
Debugging server issues related to transport protocols.

Add to your AI client

Use these steps to connect MCP SSE demo in Cursor, Claude, VS Code, and other MCP-compatible apps. The same JSON appears in the Use with menu above for one-click copy.

Cursor

Add this to your .cursor/mcp.json file in your project root, then restart Cursor.

.cursor/mcp.json

{
  "mcpServers": {
    "mcp-sse-the-vampiire": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-mcp-sse-the-vampiire"
      ]
    }
  }
}

Claude Desktop

Add this server entry to the mcpServers object in your Claude Desktop config, then restart the app.

~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows)

{
  "mcpServers": {
    "mcp-sse-the-vampiire": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-mcp-sse-the-vampiire"
      ]
    }
  }
}

Claude Code

Add this to your project's .mcp.json file. Claude Code will detect it automatically.

.mcp.json (project root)

{
  "mcpServers": {
    "mcp-sse-the-vampiire": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-mcp-sse-the-vampiire"
      ]
    }
  }
}

VS Code (Copilot)

Add this to your .vscode/mcp.json file. Requires the GitHub Copilot extension with MCP support enabled.

.vscode/mcp.json

{
  "servers": {
    "mcp-sse-the-vampiire": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-mcp-sse-the-vampiire"
      ]
    }
  }
}

Windsurf

Add this to your Windsurf MCP config file, then restart Windsurf.

~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "mcp-sse-the-vampiire": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-mcp-sse-the-vampiire"
      ]
    }
  }
}

Cline

Open Cline settings, navigate to MCP Servers, and add this server configuration.

Cline MCP Settings (via UI)

{
  "mcpServers": {
    "mcp-sse-the-vampiire": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-mcp-sse-the-vampiire"
      ]
    }
  }
}

FAQ

What is the purpose of this demo?

The demo illustrates how an MCP SSE server behaves under different runtime environments.

Is it necessary to use Bun?

No, you can also run the server using Node.js to compare the results.

Can I use this demo for production?

This demo is intended for educational and testing purposes, not for production use.

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