MCP Facade

MCP Facade

A powerful facade service that provides a unified interface for managing and interacting with multiple MCP (Machine Conversation Protocol) servers. It acts as a single entry point for agents to communicate with various MCP servers while providing robust authentication and access control.

Table of Contents

• Features
• Installation
• Configuration
• API Documentation
  • Server Management
  • Tool Management
  • Access Control
  • MCP Protocol
• Authentication
• Examples

Features

• Unified Access Point: Single interface for multiple MCP servers
• Server Management: Register, update, and manage multiple MCP servers
• Tool Management: Discover and interact with tools across all registered servers
• Authentication: JWT-based authentication with fine-grained access control
• Access Rules: Configurable access rules at the tool level
• Health Monitoring: Built-in health check endpoints
• Database Backend: PostgreSQL for storing server configurations and access rules

Run it locally

Run MCP servers (example)

Note: can skip this step if you have your mcp servers.

cd mcp-facade/mcp-servers

uv sync
source .venv/bin/activate
uv pip install -e .

# start mcp servers
uv run src/mcp_servers/main.py

Run MCP facade

# Clone the repository
git clone https://github.com/yourusername/mcp-facade.git
cd mcp-facade/mcp-facade

# Install dependencies
pnpm i

# Set up environment variables
cp .env.example .env
# Edit .env with your configuration

# Start the service
pnpm dev

Adding configuration

# add echo 
curl -X POST http://localhost:3001/api/mcp/servers \
  -H "Content-Type: application/json" \
  -d '{
    "name": "echo",
    "url": "http://127.0.0.1:3003/echo/mcp"
  }'

# add math
curl -X POST http://localhost:3001/api/mcp/servers \
  -H "Content-Type: application/json" \
  -d '{
    "name": "math",
    "url": "http://127.0.0.1:3003/math/mcp"
  }'

Using with oap-langgraph-tools-agent

# clone fork (with disabled auth)
git clone [email protected]:DmitryBe/oap-langgraph-tools-agent.git
cd oap-langgraph-tools-agent

# install deps 
uv sync
source .venv/bin/activate

# run langfraph server locally
langgraph dev

# open url
open https://smith.langchain.com/studio/?baseUrl=http://127.0.0.1:2024

# create assistant with configuration
MCPConfig
    url: http://localhost:3000/api
    tools: echo, add, subtract, multiply, divide

# start a thread by asking somehting like: compute 2 * 5 - 3

API Documentation

Server Management

Manage your MCP servers through these endpoints:

List All Servers

curl http://localhost:3001/api/mcp/servers | jq .

Get Server by Name

curl http://localhost:3001/api/mcp/servers/echo | jq .

Create Server

curl -X POST http://localhost:3001/api/mcp/servers \
  -H "Content-Type: application/json" \
  -d '{
    "name": "echo",
    "url": "http://127.0.0.1:3003/echo/mcp"
  }'

Update Server

curl -X PUT http://localhost:3001/api/mcp/servers/echo \
  -H "Content-Type: application/json" \
  -d '{
    "url": "http://127.0.0.1:3003/echo/mcp"
  }'

Delete Server

curl -X DELETE http://localhost:3001/api/mcp/servers/echo

Tool Management

List Available Tools

curl http://localhost:3000/api/mcp/tools | jq .

Call a Tool

curl -N -X POST http://localhost:3000/api/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Connection: keep-alive" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": "1",
    "method": "tools/call",
    "params": {
      "name": "echo",
      "arguments": {
        "message": "Hello, world!"
      }
    }
  }'

Access Control

The service supports fine-grained access control at the tool level. Access rules can be configured using different rule types:

• WILDCARD: Allow access to everyone
• SCOPE: Require specific OAuth scopes
• USER_ID: Restrict to specific user IDs

List All Access Rules

curl http://localhost:3001/api/access-rules | jq .

Get Rules for a Tool

curl http://localhost:3001/api/access-rules/by-tool/echo | jq .

Create Access Rule

# Allow everyone
curl -X POST http://localhost:3001/api/access-rules/by-tool/echo \
  -H "Content-Type: application/json" \
  -d '{"ruleType": "WILDCARD", "value": null}'

# Require specific scope
curl -X POST http://localhost:3001/api/access-rules/by-tool/add \
  -H "Content-Type: application/json" \
  -d '{"ruleType": "SCOPE", "value": "openid"}'

Update Access Rule

curl -X PUT http://localhost:3001/api/access-rules/2 \
  -H "Content-Type: application/json" \
  -d '{"ruleType": "USER_ID", "value": "1,2,3"}'

Delete Access Rule

curl -X DELETE http://localhost:3001/api/access-rules/3

MCP Protocol

The service implements the MCP protocol for tool interaction. Here are some common operations:

Initialize Connection

curl -N -X POST http://localhost:3001/api/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Connection: keep-alive" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "initialize",
    "params": {
      "protocolVersion": "2025-03-26",
      "capabilities": {},
      "clientInfo": {
        "name": "ExampleClient",
        "version": "1.0.0"
      }
    }
  }'

List tools

curl -N -X POST http://localhost:3000/api/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Connection: keep-alive" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 2,
    "method": "tools/list"
  }' | jq -R 'select(startswith("data: ")) | .[6:] | fromjson'

Ping Server

curl -N -X POST http://localhost:3001/api/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Connection: keep-alive" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 2,
    "method": "ping"
  }' | jq -R 'select(startswith("data: ")) | .[6:] | fromjson'

Authentication

The service uses JWT (JSON Web Tokens) for authentication. Include the JWT token in the Authorization header for authenticated requests:

curl -H "Authorization: Bearer your.jwt.token" http://localhost:3001/api/mcp/tools

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.