@smithery/gateway

Supergateway runs a MCP stdio-based servers over SSE (Server-Sent Events) with one command. This is useful for remote access, debugging, or connecting to SSE-based clients when your MCP server only speaks stdio.

Supported by superinterface.ai and supercorp.ai.

Installation & Usage

Run Supergateway via npx:

npx -y supergateway --stdio "uvx mcp-server-git"

• --port 8000: Port to listen on (default: 8000)
• --stdio: Command that runs an MCP server over stdio

Once started:

• SSE endpoint: GET http://localhost:8000/sse
• POST messages: POST http://localhost:8000/message

Example with MCP Inspector

• Run Supergateway:

  npx -y supergateway --port 8000 \
      --stdio "npx -y @modelcontextprotocol/server-filesystem /Users/MyName/Desktop"
  

• Use MCP Inspector:

  npx @modelcontextprotocol/inspector --uri http://localhost:8000/sse
  

  You can then read resources, list tools, or run other MCP actions through Supergateway.

Using with ngrok

You can use ngrok to share your local MCP server with remote clients:

npx -y supergateway --port 8000 \
    --stdio "npx -y @modelcontextprotocol/server-filesystem ."
# In another terminal:
ngrok http 8000

ngrok then provides a public URL.

Configs

Starting the MCP with Smithery configs

You can use a Smithery config by running (locally):

cat examples/exa.yaml | npx . --config -

Using Config Over MCP Wire Protocol

MCP clients can configure the server over the wire using the experimental config capability. Here's how:

• Check Capabilities: First verify the server supports config by checking its capabilities:

  {
    "capabilities": {
      "experimental": {
        "config": {}
      }
    }
  }
  

• Send Config Request: Send a JSON-RPC request to the experimental/config method:

  {
    "jsonrpc": "2.0",
    "method": "config",
    "params": {
      "config": ... // The config object over MCP
    }
  }
  

The server will validate the config against its schema and apply it if valid. Any errors in the config will be returned in the JSON-RPC response.