"Capture The Flag (CTF) cybersecurity competitions and challenges" matching MCP servers:

Provides a stable, side-effect-free MCP tool contract that enables AI workflows to be prototyped, demoed, tested, or dry-run without connecting to databases, APIs, files, or other real data sources. It enables swapping in a real data server later without changing the AI-facing interface.

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.

Enables AI assistants to access real-time web data through search, markdown scraping, and browser automation while bypassing anti-bot protections. It provides tools for web research, e-commerce monitoring, and data extraction from across the globe.

Monitor failing GitHub Actions workflows, auto-fix them with OpenCode, and retry the run — driven by a workflow_run webhook, coordinated through an MCP server.

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?'.

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?'.

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.

Model-agnostic, agent-ready Obsidian MCP server with RBAC, SLSA provenance, and native search. 163 tools across 31 domains, multi-vault, pluggable embeddings.

Enables querying Türkiye Sigorta Birliği’s Kasko Değer Listesi (vehicle insurance valuation list) through MCP, CLI, and Python, allowing natural language lookup of current and historical vehicle insurance values.

One-call Australian health and welfare data plumbing via AIHW — cited responses for practical analysis, not a data broker.

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

An MCP server that scores, enhances, and analyzes prompts for AI video and image generation models to prevent token waste on poor prompts.

AI visibility and SEO data for AI agents. Check whether ChatGPT, Claude, Perplexity and Gemini mention your brand and which sources they cite, plus keyword volume and Google Trends.

Enables querying of Hong Kong government data on elderly community care services, such as waiting times and applicant counts.

A Model Context Protocol (MCP) server that provides tools for interacting with OpenROAD and ORFS (OpenROAD Flow Scripts).

Provides 31 AI-powered crypto trading tools for Claude, Cursor, and any MCP client, enabling strategy creation, backtesting, bot deployment, copy trading, and portfolio management across multiple exchanges.

Provides access to Hong Kong climate and weather data from the Hong Kong Observatory, including current conditions, forecasts, warnings, tides, and more.

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

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.

Enables MCP-capable clients to query the tool registry, check install status, get tool recommendations for CTF or bug-bounty work, and run installed security tools through a governed execution path.

A single-process MCP server that crawls web pages, handles anti-bot challenges, converts HTML to Markdown, and caches results in PostgreSQL, providing tools to fetch and read web content.

CyberSecurity MCP Server extends Claude with real-time cybersecurity reconnaissance capabilities that Claude doesn't have by default. Instead of manually running 5 different tools across different terminals, just tell Claude "analyze google.com" and get a complete security breakdown instantly. Tools included: * WHOIS Lookup — registrar, ownership, creation/expiry dates * DNS Enumeration — A,

Enables AI assistants to securely access METU Webmail via IMAP/SMTP to list, search, read, send, reply, flag, and organize emails.

Enables AI code reviews through the CodeRabbit CLI by exposing a run_review tool that executes CodeRabbit with full flag coverage for analyzing committed, uncommitted, or all changes in a repository.

Enables full-featured editing of Word .docx files through natural language, including merge-aware table operations, bulk cell edits, footnotes/endnotes, TOC management, tracked changes, and document comparison.

Enables creating and editing PowerPoint .pptx files without corruption, with native editable SVG shapes, glued connectors, table surgery, threaded comments, live editing, and a comprehensive 138-tool MCP server surface.

Enables AI agents to perform comprehensive Excel workbook operations with verified, freshness-labeled values and structural edits that preserve formulas, tables, and references, optionally using a private Excel instance for real recalculation and export.

The open-source, self-organizing memory for all your AI tools. Persistent memory over MCP (remember, recall, observe): background agents extract entities, resolve conflicts, and keep cited syntheses current in an append-only, encrypted, single-tenant vault.

Provides AI assistants with progressive code intelligence to explore repository structure, find symbols, and assess the impact of changes using ast-grep.