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.

Related MCP server: users-mcp

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"]
    }
  }
}

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