Airline MCP Server

A Spring Boot MCP (Model Context Protocol) server that exposes flight search and booking as AI-callable tools via the Duffel API. Connect any MCP-compatible AI client (Claude, etc.) and let the AI handle the entire flight search and booking flow conversationally.

How It Works

User (natural language)
        │
        ▼
Claude AI Client  ──── discovers tools ────► MCP Server (this app)
                  ◄──── searchFlights ───────────── Duffel API
                  ◄──── bookFlight ─────────────────      │
        │                                                  ▼
        ▼                                           Real airline inventory
Natural language response

Claude reads the tool descriptions, decides which tools to call, extracts parameters from the conversation, and returns a natural language response. No routing logic needed in your client code.

Tech Stack

Layer	Technology
Language	Java 26
Framework	Spring Boot 4.1.0
AI / MCP	Spring AI 2.0.0-RC2 (spring-ai-starter-mcp-server-webmvc)
Protocol	MCP STREAMABLE (HTTP + SSE)
Flight API	Duffel REST API v2
JSON	Jackson

Project Structure

src/main/java/com/aie/airline/
├── AirlineApplication.java          # Spring Boot entry point + bean wiring
├── service/
│   └── AirlineTools.java            # @Tool methods exposed to Claude
├── repository/
│   └── FlightProvider.java          # Interface: search / price / book
├── provider/
│   └── DuffelProvider.java          # Duffel API implementation
├── model/
│   ├── Flight.java                  # Search result
│   ├── FlightQuery.java             # Search parameters
│   ├── PricedOffer.java             # Re-validated offer with expiry
│   ├── Passenger.java               # Traveller details
│   ├── BookingResult.java           # PNR + confirmation
│   └── BookingRequest.java
└── exception/
    └── OfferExpiredException.java   # Thrown when Duffel offer expires

Prerequisites

• Java 21+
• Maven 3.8+
• Duffel account with API token → app.duffel.com

Setup

1. Get a Duffel API token

Sign up at app.duffel.com, go to Developers → Access tokens, create a test token.

2. Configure the token

Edit src/main/resources/application.yml:

spring:
  ai:
    mcp:
      server:
        name: airline-tickets
        version: 1.0.0
        protocol: STREAMABLE
        type: SYNC
server:
  port: 8080

duffel:
  token: YOUR_DUFFEL_TOKEN_HERE

3. Run

mvn spring-boot:run

Server starts on http://localhost:8080. The MCP endpoint is at POST /mcp.

MCP Tools Exposed

searchFlights

Search available flights between two cities.

Parameter	Type	Description
origin	String	IATA code or city, e.g. BLR
destination	String	IATA code or city, e.g. DXB
date	String	Travel date in YYYY-MM-DD
passengers	int	Number of adult passengers

Returns: list of flights with offer IDs, airline, times, and price.

bookFlight

Book a specific offer. Charges payment — irreversible.

Parameter	Type	Description
offerId	String	Offer ID from searchFlights
givenName	String	First name as on ID
familyName	String	Last name as on ID
bornOn	String	Date of birth YYYY-MM-DD
gender	String	m or f
title	String	mr, ms, mrs, or dr
email	String	Passenger email
phone	String	Phone with country code, e.g. +919876543210

Returns: booking reference (PNR) and confirmation status.

Testing the MCP Server Directly

Step 1 — Initialize and capture session ID

SESSION=$(curl -s -X POST http://localhost:8080/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: text/event-stream, application/json" \
  -d '{
    "jsonrpc": "2.0", "id": 1, "method": "initialize",
    "params": {
      "

... [View full README on GitHub](https://github.com/Virendrakushwaha/airline-mcp-server#readme)