"Hack The Box" matching MCP servers:

Enables AI assistants to interact with humans through GUI dialogs for text input, choices, confirmations, and information display.

Enables AI assistants like Claude to interact with humans through intuitive GUI dialogs, supporting text input, choices, confirmations, and information displays.

MCP server that resolves postal/ZIP codes to place names, states, and coordinates using Zippopotam.us. Free, no API key required.

Enables real-time domain registration lookups via RDAP, including availability, expiration, and registrar details, with no API key required. Supports natural language queries like 'is example.com available?' or 'when does example.com expire?'.

Relays error logs from other MCP servers when an LLM call fails and the returned error message is unclear, helping the model handle errors more intelligently.

An MCP front-end for AnB. The tool surface is "use-don't-reveal": no tool returns a plaintext secret. Reveal paths require a TTY the server doesn't have, so the no-reveal guarantee is structural, not prompt-based — it holds even against a prompt-injected agent. Runs as a dedicated, narrowly-scoped AnB identity; exec is default-deny (only allowlist rules tagged scope=mcp run); command output

Ask Claude "What's the cash rate?" or "What's AUD/USD today?" and get the real number from the Reserve Bank of Australia. Wraps RBA's F-tables with plain-English access to interest rates, FX rates, deposit rates, and mortgage rates.

Enables currency conversion and exchange rate lookups using real ECB reference rates, free and without an API key. Supports natural language queries like 'convert 100 USD to EUR' or 'what's the exchange rate between GBP and JPY?'.

A multi-agent Retrieval-Augmented Generation system exposed as an MCP server. Ask a question and a LangGraph pipeline plans the retrieval, pulls evidence from a pgvector knowledge base, optionally augments it with live web research, drafts a cited answer, and then self-critiques it for grounding — revising until the answer is supported by the sources.

Provides real, official public holiday data for ~100 countries with tools to list holidays for a year and check if a specific date is a holiday. Free, no API key required, powered by Nager.Date.

Provides real-time air quality data (US AQI, PM2.5, PM10, ozone, NO2, SO2, CO) for any city via natural language, using free Open-Meteo data and a single tool.

MCP server for generating negative-space print supports for 3D models (STL/OBJ/STEP) via the negative.support API.

MCP server that searches the web, reads pages, and returns concise summaries with cited sources via the research_web and read_url tools.

MCP server for searching and retrieving full-text pages from the Library of Congress, including newspapers, books, and manuscripts, via the loc.gov API.

Generates UML and other diagrams (30+ types) via the Model Context Protocol, supporting multiple output formats and deployment options.

Enables version-aware retrieval over the Neutrinos documentation corpus using hybrid BM25/dense search, reranking, and link-graph expansion to answer queries accurately for the user's specific product version.

Provides real-time cryptocurrency prices, market cap, and 24h change using CoinGecko, with free access and no API key required.

A Model Context Protocol (MCP) server for Firebird databases intended for local use. It reads connection details from FlameRobin's fr_databases.conf so no extra configuration is needed — if you have FlameRobin set up with your Firebird databases, this server works out of the box.

Searches Lithuanian legislation by title and fetches full text from the Register of Legal Acts (TAR) via the data.gov.lt open-data API, with verifiable citations.

A reference implementation of the mcp-lens pattern for progressive disclosure in MCP servers. It exposes three stable meta-tools to search, inspect, and execute capabilities, keeping tool-definition costs constant as the catalog grows.