Stdio-based MCP servers communicate through standard input/output (stdin/stdout) rather than HTTP endpoints. This approach is particularly useful for local development and testing.

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Overview

Unlike HTTP-based MCP servers that expose REST endpoints, stdio-based servers:

  • Communicate through standard input and output streams
  • Use JSON-RPC over stdio for message exchange
  • Provide lower latency for local operations

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Exposing Stdio Servers as HTTP Endpoints

Use mcp-proxy to convert stdio servers to HTTP endpoints.

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Using mcp-proxy

mcp-proxy can wrap any stdio-based MCP server command to expose it as HTTP endpoints:

# Install TypeScript version (https://github.com/punkpeye/mcp-proxy)
npm install mcp-proxy

# Wrap any stdio-based MCP server command
npx mcp-proxy --port 8000 --host 0.0.0.0 --server stream --debug <your-stdio-command>

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# Install Python version (https://github.com/sparfenyuk/mcp-proxy)
uv tool install mcp-proxy
# or
pipx install mcp-proxy

# Wrap any stdio-based MCP server command
mcp-proxy --port 8000 --host 0.0.0.0 --transport streamablehttp --debug <your-stdio-command>

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Benefits of Using mcp-proxy

  • Convert any stdio server to HTTP endpoints
  • Support multiple concurrent connections
  • Access stdio servers over the network
  • CORS enabled by default

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Integration with TrueFoundry

Configure your MCP server in TrueFoundry as an HTTP server:

  • Server Type: HTTP (not stdio)
  • Endpoint URL: http://your-proxy-host:8000/mcp

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Example: MongoDB MCP Server

Complete setup for MongoDB MCP server with stdio and proxy:

# Install MongoDB MCP server
npm install -g mongodb-mcp-server

# Option 1: Direct stdio usage
npx mongodb-mcp-server

# Option 2: Via TypeScript mcp-proxy for HTTP endpoints
npx mcp-proxy --port 8000 --host 0.0.0.0 --server stream --debug npx mongodb-mcp-server

# Option 3: Via Python mcp-proxy (alternative)
mcp-proxy --port 8000 --host 0.0.0.0 npx mongodb-mcp-server

# Test proxy endpoints
curl http://localhost:8000/mcp  # HTTP endpoint

MongoDB MCP Server

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TrueFoundry Service Deployment

Deploy any stdio-based MCP server as a TrueFoundry service. Example with MongoDB MCP server:

type: service
name: mongodb-mcp
image:
  type: image
  image_uri: node:24
  command: >-
    npx -y mcp-proxy --port 8000 --host 0.0.0.0 --server stream  --debug npx
    mongodb-mcp-server
ports:
  - host: <your-host>
    port: 8000
    expose: true
    protocol: TCP
    app_protocol: http
env:
  MDB_MCP_CONNECTION_STRING: mongodb://root:password@mongodb.default.svc.cluster.local:27017
workspace_fqn: <your-workspace>
replicas: 1
allow_interception: false
resources:
  node:
    type: node_selector
    capacity_type: spot
  cpu_request: 0.2
  cpu_limit: 0.5
  memory_request: 2000
  memory_limit: 5000
  ephemeral_storage_request: 1000
  ephemeral_storage_limit: 2000

Customizing for Different MCP Servers:

Replace the command with your specific MCP server:

# Using TypeScript mcp-proxy (default)
command: >-
  npx -y mcp-proxy --port 8000 --host 0.0.0.0 --server stream --debug python your-server.py

# Using Python mcp-proxy (alternative)
command: >-
  pip install mcp-proxy && mcp-proxy --port 8000 --host 0.0.0.0 python your-server.py

# For TypeScript MCP servers  
command: >-
  npx -y mcp-proxy --port 8000 --host 0.0.0.0 --server stream --shell tsx your-server.ts

# For Node.js MCP servers
command: >-
  npx -y mcp-proxy --port 8000 --host 0.0.0.0 --server stream --debug node your-server.js