MCP Access Point

MCP Access Point is a lightweight protocol conversion gateway tool designed to establish a communication bridge between traditional HTTP services and MCP (Model Context Protocol) clients. It enables MCP clients to interact directly with existing HTTP services without requiring any server-side interface modifications.

Introduction

This project is built on Pingora - an ultra-high performance gateway proxy library capable of supporting massive-scale request proxy services. Pingora has been used to build services that handle core traffic for the Cloudflare platform, consistently serving over 40 million requests per second across the internet for years. It has become the technical cornerstone supporting a significant proportion of traffic on the Cloudflare platform.

HTTP to MCP

This mode allows clients like Cursor Desktop to communicate with remote HTTP servers through SSE, even when the servers themselves don't support the SSE protocol.

• Example setup includes two services:
  • Service 1 runs locally at 127.0.0.1:8090
  • Service 2 runs remotely at api.example.com
• Through the MCP Access Point, both services can be converted to MCP services without any code modifications.
• Clients communicate with Service 1 and Service 2 via the MCP protocol. The MCP Access Point automatically distinguishes MCP requests and forwards them to the appropriate backend services.

graph LR
   A["Cursor Desktop"] <--> |SSE| B["MCP Access Point"]
   A2["Other Desktop"] <--> |Streamable Http| B["MCP Access Point"]
   B <--> |http 127.0.0.1:8090| C1["Existing API Server"]
   B <--> |https//api.example.com| C2["Existing API Server"]
  
   style A2 fill:#ffe6f9,stroke:#333,color:black,stroke-width:2px
   style A fill:#ffe6f9,stroke:#333,color:black,stroke-width:2px
   style B fill:#e6e6af,stroke:#333,color:black,stroke-width:2px
   style C1 fill:#e6ffe6,stroke:#333,color:black,stroke-width:2px
   style C2 fill:#e6ffd6,stroke:#333,color:black,stroke-width:2px

Transport Type (Specification)

Currently supports SSE and Streamable HTTP protocols:

• ✅ Streamable HTTP (stateless) 2024-03-26

  • All services: ip:port/mcp/
  • Single service: ip:port/api/{service_id}/mcp/

• ✅ SSE 2024-11-05

  • All services: ip:port/sse
  • Single service: ip:port/api/{service_id}/sse/

use IP:PORT/sse for SSE use IP:PORT/mcp/ for Streamable HTTP

Supported MCP clients

• ✅ MCP Inspector
• ✅ Cursor Desktop

Core Features

• Protocol Conversion: Seamless conversion between HTTP and MCP protocols
• Zero-Intrusive Integration: Full compatibility with existing HTTP services
• Client Empowerment: Enables MCP clients to directly call standard HTTP services
• Lightweight Proxy: Minimalist architecture with efficient protocol conversion
• Multi-tenancy: Independent configuration and endpoints for each tenant

Quick Start

Installation

# Install from source
git clone https://github.com/sxhxliang/mcp-access-point.git
cd mcp-access-point
cargo run -- -c config.yaml

# Use inspector for debugging (start service first)
npx @modelcontextprotocol/inspector node build/index.js
# Access http://127.0.0.1:6274/
# Select "see" and enter 0.0.0.0:8080/sse, then click connect
# or select "Streamable HTTP" and enter 0.0.0.0:8080/mcp/

Multi-tenancy Support

The MCP Access Gateway supports multi-tenancy, where each tenant can configure multiple MCP services accessible via:

• /api/{mcp-service-id}/sse (for SSE)
• /api/{mcp-service-id}/mcp (for Streamable HTTP)

Example configuration:

# config.yaml example (supports multiple services)

mcps:
  - id: service-1 # Access via /api/service-1/sse or /api/service-1/mcp
    ... # Service configuration
  - id: service-2 # Access via /api/service-2/sse or /api/service-2/mcp
    ... # Service configuration
  - id: service-3 # Access via /api/service-3/sse or /api/service-3/mcp
    ... # Service configuration

To access all services simultaneously, use:

• 0.0.0.0:8080/mcp/ (Streamable HTTP)
• 0.0.0.0:8080/sse (SSE)

Configuration Details

1. -c config.yaml
   • -c (or --config) specifies the configuration file path (config.yaml).
   • This file defines the APIs that the MCP Access Point will proxy and convert.

config.yaml Example

The configuration file supports multi-tenancy, allowing independent configuration of upstream services and routing rules for each MCP service. Key configuration items include:

1. mcps - MCP service list

   • id: Unique service identifier used to generate access paths
   • upstream_id: Associated upstream service ID
   • path: OpenAPI specification file path (local or remote)
   • routes: Custom routing configuration (optional)
   • upstream: Upstream service specific configuration (optional)

2. upstreams - Upstream service configuration

   • id: Upstream service ID
   • nodes: Backend node addresses and weights
   • type: Load balancing algorithm (roundrobin/random/ip_hash)
   • scheme: Upstream protocol (http/https)
   • pass_host: HTTP Host header handling
   • upstream_host: Override Host header value

Complete configuration example:

# config.yaml example (supports multiple services)
mcps:
  - id: service-1 # Unique identifier, accessible via /api/service-1/sse or /api/service-1/mcp
    upstream_id: 1
    path: config/openapi_for_demo_patch1.json # Local OpenAPI spec path

  - id: service-2 # Unique identifier
    upstream_id: 2
    path: https://petstore.swagger.io/v2/swagger.json # Remote OpenAPI spec

  - id: service-3 
    upstream_id: 3
    routes: # Custom routing
      - id: 1
        operation_id: get_weather
        uri: /points/{latitude},{longitude}
        method: GET
        meta:
          name: Get Weather
          description: Retrieve weather information by coordinates
          inputSchema: # Optional input validation
            type: object
            required:
              - latitude
              - longitude
            properties:
              latitude:
                type: number
                minimum: -90
                maximum: 90
              longitude:
                type: number
                minimum: -180
                maximum: 180

upstreams: # Required upstream configuration
  - id: 1
    headers: # Headers to send to upstream service
      X-API-Key: "12345-abcdef"        # API key
      Authorization: "Bearer token123" # Bearer token
      User-Agent: "MyApp/1.0"          # User agent
      Accept: "application/json"       # Accept header
    nodes: # Backend nodes (IP or domain)
      "127.0.0.1:8090": 1 # Format: address:weight

  - id: 2 
    nodes:
      "127.0.0.1:8091": 1

  - id: 3 
    nodes:
      "api.weather.gov": 1
    type: roundrobin # Load balancing algorithm
    scheme: https # Protocol
    pass_host: rewrite # Host header handling
    upstream_host: api.weather.gov # Override Host

To run the MCP Access Gateway with config file:

cargo run -- -c config.yaml

Running via Docker

Build Docker Image (Optional)

# Clone repository
git clone https://github.com/sxhxliang/mcp-access-point.git
cd mcp-access-point

# Build image
docker build -t liangshihua/mcp-access-point:latest .

Run Docker Container

# Using environment variables (service running on host)
# Note: Replace /path/to/your/config.yaml with actual path

docker run -d --name mcp-access-point --rm \
  -p 8080:8080 \
  -e port=8080 \
  -v /path/to/your/config.yaml:/app/config/config.yaml \
  liangshihua/mcp-access-point:latest

Environment Variables

• port: MCP Access Point listening port (default: 8080)

Typical Use Cases

• Progressive Architecture Migration: Facilitate gradual transition from HTTP to MCP
• Hybrid Architecture Support: Reuse existing HTTP infrastructure within MCP ecosystem
• Protocol Compatibility: Build hybrid systems supporting both protocols

Example Scenario:
When MCP-based AI clients need to interface with legacy HTTP microservices, the MCP Access Gateway acts as a middleware layer enabling seamless protocol conversion.