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) 2025-03-26

  • 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
• ✅ Windsurf
• ✅ VS Code
• ✅ Trae

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
• Runtime Configuration Management: Dynamic configuration updates without service restart
• Admin API: RESTful API for real-time configuration management

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 "SSE" 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. Supports local files (e.g., config/openapi.json) and remote HTTP/HTTPS URLs (e.g., https://petstore.swagger.io/v2/swagger.json). Both JSON and YAML formats are supported.
   • 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

Run Locally for quick start

# 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 \
  ghcr.io/sxhxliang/mcp-access-point:main

Build Docker Image (Optional)

• install docker
• clone repository and build image

# 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.

Many thanks to @limcheekin for writing an article with a practical example: https://limcheekin.medium.com/building-your-first-no-code-mcp-server-the-fabric-integration-story-90da58cdbe1f

Runtime Configuration Management

The MCP Access Point now supports dynamic configuration management through a RESTful Admin API, allowing you to update configurations without restarting the service.

Admin API Features

• Real-time Configuration Updates: Modify upstreams, services, routes, and other resources on-the-fly
• Dependency Validation: Automatic validation of resource dependencies before changes
• Batch Operations: Execute multiple configuration changes atomically
• Configuration Validation: Dry-run mode to validate changes before applying
• Resource Statistics: Monitor and track configuration state

Admin API Configuration

Add the following to your config.yaml to enable the Admin API:

access_point:
  admin:
    address: "127.0.0.1:8081"  # Admin API listening address
    api_key: "your-api-key"    # Optional API key for authentication

Admin API Endpoints

Resource Management

• GET /admin/resources - Get resource summary and statistics
• GET /admin/resources/{type} - List all resources of a specific type
• GET /admin/resources/{type}/{id} - Get a specific resource
• POST /admin/resources/{type}/{id} - Create a new resource
• PUT /admin/resources/{type}/{id} - Update an existing resource
• DELETE /admin/resources/{type}/{id} - Delete a resource

Advanced Operations

• POST /admin/validate/{type}/{id} - Validate resource configuration
• POST /admin/batch - Execute batch operations
• POST /admin/reload/{type} - Reload a specific resource type
• POST /admin/reload/config - Reload full configuration from file (defaults to config.yaml). Optional JSON body: { "config_path": "path/to/config.yaml" }

Supported Resource Types

• upstreams - Backend server configurations
• services - Service definitions
• routes - Routing rules
• global_rules - Global plugin rules
• mcp_services - MCP service configurations
• ssls - SSL certificate configurations

Admin API Examples

Create a new upstream

curl -X POST http://localhost:8081/admin/resources/upstreams/my-upstream \
  -H "Content-Type: application/json" \
  -d '{
    "id": "my-upstream",
    "type": "RoundRobin",
    "nodes": ["127.0.0.1:8001", "127.0.0.1:8002"],
    "timeout": {
      "connect": 5,
      "read": 10,
      "send": 10
    }
  }'

Create a service

curl -X POST http://localhost:8081/admin/resources/services/my-service \
  -H "Content-Type: application/json" \
  -d '{
    "id": "my-service",
    "upstream_id": "my-upstream",
    "hosts": ["api.example.com"]
  }'

Batch operations

curl -X POST http://localhost:8081/admin/batch \
  -H "Content-Type: application/json" \
  -d '{
    "dry_run": false,
    "operations": [
      {
        "operation_type": "create",
        "resource_type": "upstreams",
        "resource_id": "batch-upstream",
        "data": {
          "id": "batch-upstream",
          "type": "Random",
          "nodes": ["192.168.1.10:8080"]
        }
      },
      {
        "operation_type": "create",
        "resource_type": "services",
        "resource_id": "batch-service",
        "data": {
          "id": "batch-service",
          "upstream_id": "batch-upstream"
        }
      }
    ]
  }'

Get resource statistics

curl http://localhost:8081/admin/resources

Admin Dashboard UI

• Route: GET /admin serves a built-in dashboard (static/admin_dashboard.html).
  1. mcp_services, 2) ssls, 3) global_rules, 4) routes, 5) upstreams, 6) services.
• Each card shows count and a formatted last_updated derived from the API response.

Reload configuration from file

# Uses default config.yaml
curl -X POST http://localhost:8081/admin/reload/config \
  -H "Content-Type: application/json" \
  -H "x-api-key: your-api-key"

# Or specify a different config path
curl -X POST http://localhost:8081/admin/reload/config \
  -H "Content-Type: application/json" \
  -H "x-api-key: your-api-key" \
  -d '{"config_path": "./config.yaml"}'

Testing the Admin API

Use the provided test script to verify Admin API functionality:

# Make the test script executable
chmod +x test-admin-api.sh

# Run comprehensive API tests
./test-admin-api.sh

For detailed Admin API documentation, see RUNTIME_CONFIG_API.md.

Contribution Guidelines

1. Fork this repository.
2. Create a branch and commit your changes.
3. Create a pull request and wait for it to be merged.
4. Make sure your code follows the Rust coding standards.