# Changelog

All notable changes to the GDS Mock MCP Server will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [0.1.0] - 2026-04-08

### Added
- Initial release of GDS Mock MCP Server
- **Flight Search and Booking** (User Story 1 - MVP)
  - `searchFlights` tool: Search for flights between airports with realistic pricing
  - `bookFlight` tool: Create flight bookings with passenger details
  - Mock data: 100+ airports, 30+ airlines, deterministic flight generation
  - Support for economy, business, and first class cabins
  - Realistic pricing ($200-$2500+ based on route and class)
  
- **Session Management** (User Story 4)
  - Concurrent session support with UUID v4 session IDs
  - Session isolation: bookings scoped to sessions with zero data leakage
  - Session TTL management (1 hour default, configurable)
  - Activity tracking and automatic cleanup
  
- **Remote Access** (User Story 6)
  - **MCP 2025-11-25 Streamable HTTP transport** (HTTP/1.1 + SSE)
  - Protocol version validation middleware (strict 2025-11-25)
  - IP-based rate limiting (100 req/min default, Valkey-backed)
  - CORS middleware with permissive wildcard policy
  - Health check endpoint (`/health`)
  - CLI arguments: `--remote`, `--port`, `--host`, `--verbose`, `--log-level`
  - Dual transport support: stdio (default) or HTTP
  - SSE polling pattern with Last-Event-ID resumption
  - Example remote client demonstrating SSE connection
  - Nginx reverse proxy configuration template
  
- **Hotel Search and Bundling** (User Story 2)
  - `searchHotels` tool: Search hotels by city with pricing tiers
  - `bookHotel` tool: Create hotel bookings and bundle with flights
  - Mock data: 50+ properties across major cities (3-5 star ratings)
  - Realistic pricing: budget ($80-$150), midrange ($150-$300), luxury ($300-$800)
  - Multi-service bundling: combine hotels with flights under single PNR
  
- **Car Rental Integration** (User Story 3)
  - `searchCars` tool: Search car rentals by pickup/dropoff location
  - `bookCar` tool: Create car rental bookings and bundle with flights/hotels
  - Mock data: 8 rental companies, 8 vehicle categories
  - Complete travel package support: flights + hotels + cars under one PNR
  
- **Booking Management Tools**
  - `retrieveBooking` tool: Fetch booking details by PNR
  - `cancelBooking` tool: Cancel bookings with status validation
  - `listBookings` tool: List all bookings in current session
  - `getSessionInfo` tool: View session metadata
  - `clearSession` tool: Clear session data
  
- **Infrastructure**
  - Valkey 8.0+ integration for session and PNR storage
  - Structured logging with Pino
  - MCP error codes and error handling
  - JSON schema validation
  - PNR generation with TEST- prefix (base32 encoding)
  - Docker Compose configuration for Valkey
  - Multi-stage Dockerfile with non-root user
  - ESLint and Prettier configuration
  
### Technical Details
- **Node.js 20 LTS** with ES modules
- **@modelcontextprotocol/sdk v1.0.4+** for MCP protocol
- **ioredis v5.4.1** for Valkey/Redis client
- **Pino v9.5.0** for structured logging
- **Express v4.18+** for HTTP middleware
- **express-rate-limit v7.1+** for IP-based rate limiting
- **CORS v2.8+** for cross-origin support

### Security
- PNRs prefixed with TEST- to prevent confusion with production
- No real external API calls (100% self-contained)
- Rate limiting on remote access (100 req/min per IP)
- Localhost binding by default (127.0.0.1) per MCP security
- Non-root Docker user
- Session isolation with cryptographically secure UUIDs

### Documentation
- Comprehensive README with installation and usage instructions
- SAFETY_DISCLAIMER.md emphasizing testing/demo purpose only
- Inline JSDoc comments for all public functions
- Example remote client with SSE demonstration
- Nginx configuration template for optional HTTP/2 upgrade

## [Unreleased]

### Planned
- Additional search filters (airline preference, hotel amenities, car features)
- Enhanced error messages with suggested corrections
- Metrics and monitoring endpoints
- Load testing and performance optimization
- Additional mock data for global coverage

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**Note**: This is a mock server for testing and demonstration purposes only. All data is simulated. No real travel bookings are created.