What is hotelzero CLAUDE.md?

A project instruction file for HotelZero, an MCP server that searches Booking.com hotels through automated web browsing. It documents commands, tests, and configuration such as proxy settings.

Use it when developing HotelZero, running its TypeScript build and test commands, starting the server, or configuring hotel-search browser automation.

It gives coding agents the repository-specific information needed to build, run, test, and maintain the project consistently.

How insprd/hotelzero configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to insprd/hotelzero. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/insprd/hotelzero/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/insprd/hotelzero

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/insprd/hotelzero/claude-md/github.svg)](https://agentmods.dev/instructions/insprd/hotelzero/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/insprd/hotelzero/claude-md"><img src="https://agentmods.dev/badge/instructions/insprd/hotelzero/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/insprd/hotelzero/claude-md"><img src="https://agentmods.dev/badge/instructions/insprd/hotelzero/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,568 This file is loaded in full into every session.

When invoked 1,568 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01568	$0.01568
Opus 5.5	$0.00627	$0.00627
Sonnet 5.5	$0.00314	$0.00314
Haiku 4.5	$0.00157	$0.00157

Measured 2mo ago against content hash 474d08d8dc9c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

hotelzero CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Overview

HotelZero is an MCP (Model Context Protocol) server that searches hotels on Booking.com using Playwright browser automation. It provides 80+ filters for precise hotel searches and implements anti-bot detection measures including user agent rotation, session persistence, and proxy support.

Development Commands

# Build
npm run build              # Compile TypeScript to dist/

# Development
npm run dev                # Run server in development mode with tsx

# Testing
npm test                   # Run all tests with vitest
npm run test:watch         # Run tests in watch mode
npm run test:ui            # Open vitest UI
npm run test:search        # Run search tests only
npm run test:details       # Run hotel details tests only
npm run test:reviews       # Run reviews tests only
npm run test:selectors     # Run selector tests only
npm run test:calendar      # Run price calendar tests only

# Production
npm start                  # Run the built server (requires build first)

Environment Variables

HOTELZERO_PROXY: Proxy server URL (HTTP or SOCKS5, with optional auth)
HOTELZERO_LOG_LEVEL: Log verbosity (trace, debug, info, warn, error, fatal, silent)
HOTELZERO_SESSION_PATH: Custom session file location (default: ~/.hotelzero/session.json, empty string to disable)

Architecture

Core Components

src/index.ts - MCP server implementation

Defines 8 MCP tools: find_hotels, search_hotels, get_hotel_details, check_availability, get_reviews, get_price_calendar, compare_hotels, get_hotel_images
Implements Zod schemas for input validation
Handles tool routing and error formatting
Server runs on stdio transport for MCP communication

src/browser.ts - Playwright automation engine

HotelBrowser class manages browser lifecycle and session persistence
Filter code mappings: 20+ categories mapping friendly names to Booking.com's nflt URL parameters
User agent rotation: 14 realistic browser profiles
Session management: Saves/loads cookies and localStorage to reduce CAPTCHA challenges
Retry logic: Exponential backoff with jitter for transient failures
Custom error types: HotelSearchError with error codes and retryable flags

Read the full file on GitHub · 173 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 173 lines · 1,568 tokens per session scan A 474d08d8dc9c

Subscribe to this mod's changes

hotelzero CLAUDE.md is an instructions file published in the GitHub repository insprd/hotelzero (1 stars, last pushed 8mo ago), licensed MIT. It adds 1,568 tokens to every session, about $0.0063 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

hotelzero CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
hotelzero CLAUDE.mdinsprd/hotelzero	Instructions file	1	8mo ago	MIT	A	1,568	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

hotelzero: Instructions file for Claude Code