API Client → Business Logic → MCP Tools

Small Python example showing how to reuse an API client and business logic from both normal application code and MCP tools.

Structure

src/example/
├── api/
│   └── api_client.py
├── business/
│   └── service.py
├── mcp/
│   └── server.py
└── main.py

The example exposes 5 operations:

1. get_user
2. list_users
3. create_user
4. update_user
5. delete_user

The MCP layer is deliberately thin: it validates MCP inputs and delegates to the business service. The business service delegates HTTP work to the API client.

Install

python -m venv .venv
# Windows:
.venv\Scripts\activate
# Linux/macOS:
source .venv/bin/activate

pip install -r requirements.txt

Run the MCP server

python -m src.example.mcp.server

Or configure the MCP client to launch:

python -m src.example.mcp.server

Use MCP server

Via terminal

{"jsonrpc":"2.0","method":"tools/list","id":1}

Or Claude

{
  "mcpServers": {
    "example-users": {
      "command": "python",
      "args": ["-m", "src.example.mcp.server"]
    }
  }
}

Or vía WebSocket (Railway deployment)

Live on Railway:

wss://claude-ia-mcp-tools-staging.up.railway.app

Connect with Python:

import asyncio
import json
import websockets

async def call_mcp():
    uri = "wss://claude-ia-mcp-tools-staging.up.railway.app"
    async with websockets.connect(uri) as ws:
        # Call get_user
        request = {
            "jsonrpc": "2.0",
            "method": "tools/call",
            "params": {
                "name": "get_user",
                "arguments": {"user_id": 1}
            },
            "id": 1
        }
        await ws.send(json.dumps(request))
        response = await ws.recv()
        print(json.loads(response))

asyncio.run(call_mcp())

Configure in Claude Desktop:

{
  "mcpServers": {
    "claude-ia-mcp-tools": {
      "command": "uvx",
      "args": ["mcp-websocket-client", "wss://claude-ia-mcp-tools-staging.up.railway.app"]
    }
  }
}

Available Tools:

• get_user - Get one user by ID
• list_users - List all users
• create_user - Create a new user
• update_user - Update user name/email
• delete_user - Delete a user

Important

This is a self-contained architectural example. The API client uses https://jsonplaceholder.typicode.com as a public demo API.

For a real API, replace ApiClient implementation and keep the business/MCP interfaces essentially unchanged.

Test workflow execution