Travel Server MCP

A modular MCP server for searching flights using the Duffel API. Built for extensibility, maintainability, and clarity.

Step-by-Step Tutorial

If you want a guided walkthrough on how this server was created from scratch, check out the Step-by-Step Tutorial.

Features

• Search for flights between any two airports using the Duffel API

• Granular, well-documented codebase with clear separation of concerns

• Detailed debug logging returned with every search

• Easily extensible for new tools, models, or providers

Project Structure

travelserver/
├── main.py                # Entrypoint: sets up and runs the MCP server
├── duffel_client.py       # Duffel API HTTP logic (search_flights)
├── models/
│   ├── __init__.py
│   ├── flight_search_params.py
│   └── flight_offer.py
├── tools/
│   └── flight_tools.py    # MCP tool for flight search
├── .env                   # (not committed) Your Duffel API key
├── pyproject.toml         # Project dependencies
└── ...

Setup

1. Clone the repository

   git clone https://github.com/kidehen/mcp-travel-server.git
   cd mcp-travel-server

2. Create and activate a virtual environment with uv:

   uv venv
   source .venv/bin/activate

3. Install dependencies with uv:

   uv pip install -e .

4. Create a .env file in the project root:

   DUFFEL_ACCESS_TOKEN=your_duffel_api_key_here

Running the Server

Run the server using uv:

uv run main.py

Claude Desktop MCP Server Configuration

{
  "mcpServers": {
    "travel-server": {
      "command": "/opt/homebrew/bin/uv",
      "args": [
        "--directory",
        "/Users/jidehen/Documents/Projects/mcp-servers/travelserver",
        "run",
        "main.py"
      ]
    }
  }
}

Usage

• The MCP server exposes a get_flights tool for searching flights.

• You can connect this server to an MCP-compatible client (e.g., Claude Desktop).

• When a user asks about flights, the client will call the get_flights tool with the appropriate parameters.

• The server returns a list of flight offers and a detailed debug log for troubleshooting.

Environment Variables

• DUFFEL_ACCESS_TOKEN: Your Duffel API key (required, set in .env)

Extending the Project

• Add new models to models/ (one per file)

• Add new tools to tools/

• Add new API integrations to their own directories (e.g., duffel/, amadeus/)

• Keep configuration in config/ as needed

FAQ

• How does the MCP client know how to interact with the Duffel API?

  The MCP client never talks to Duffel directly. It calls this MCP server's tool, which handles all Duffel API logic internally and returns results to the client.

• How does the MCP client know to trigger this server for flight queries?

  The MCP client discovers all available MCP servers and their tools. When a user asks about flights, the client uses natural language understanding to match the user's intent to the get_flights tool, and then calls it.

License

MIT

Available Tools

get-flights

Search for available flights between two locations.

Parameters:

• origin: Origin airport code (e.g., 'LHR')

• destination: Destination airport code (e.g., 'JFK')

• departure_date: Departure date in YYYY-MM-DD format

• return_date (optional): Return date in YYYY-MM-DD format

• passengers (optional): Number of adult passengers (default: 1)

• cabin_class (optional): Cabin class (economy, business, first) (default: economy)

Example response:

[
  {
    "airline": "British Airways",
    "flight_number": "BA178",
    "departure_time": "2024-03-20T10:00:00",
    "arrival_time": "2024-03-20T13:00:00",
    "price": 299.99,
    "currency": "USD",
    "stops": 0
  }
]