"Services or tools available for free without requiring an API key" matching MCP servers:

MCP server enabling AI agents to use secrets (API keys, tokens) via encrypted vault, executing HTTP/shell/SSH actions server-side while never exposing secret values to the AI.

An MCP (Multi-Agent Conversation Protocol) server that enables interaction with Google's Managed Service for Microsoft Active Directory through its OpenAPI, allowing users to manage identity resources through natural language.

A passive MCP server that exposes a toolbox of executable tools (shell, network, HTTP, AI search, SSH, S3 file operations) to autonomous agents via Streamable HTTP, with strong security features including Docker sandboxing and WAF.

Enables coding agents to perform file, search, patch, git, process, test, package, network, and system operations through 60 typed MCP tools with structured inputs/outputs, structured errors, and a full event journal, replacing terminal use with a typed machine API.

A local MCP server that lets Hermes supervise Claude Code, delegating focused coding, research, or review tasks to the Claude Code CLI and managing worker sessions, background jobs, cancellations, and read-only reviews.

Enables n8n AI agents to manage MikroTik routers via SSH/SSE, providing tools for firewall, DNS, DHCP, WireGuard, interfaces, queues, backup, users, logs, and routes.

GDB Enhanced Features MCP server for remote debugging and CTF exploitation with 41 specialized tools including ROP search, format-string detection, and memory patching.

Enables MCP clients to invoke common Kali Linux pentesting tools directly as tool calls, with each binary executed safely without a shell.

AI-powered MCP server for managing Proxmox VE VMs and containers with built-in governance, audit logging, and reversibility.

MCP server wrapping DeepSeek's agent harness tools into minimal/standard modes, enabling persistent shell, file editing, search, job management, and more via natural language.

Enables dynamic creation and execution of custom tools/functions in multiple programming languages at runtime, exposing them to MCP clients like Claude.

A SQL Server CLI and MCP server for Claude Code that supports standard SQL Server authentication for database interaction and management. It enables users to perform schema exploration, execute queries, and manage data records with built-in SQL injection prevention.

Fork of @cyanheads toolkit MCP server. Added encoding functions, removed system network functions.

MCP server that gives AI coding agents (Claude Code, Cursor, Cline, etc.) access to multiple AI models through Antigravity CLI and OpenAI Codex CLI, enabling mid-conversation model consultation and code review.

Enables interaction with lightning addresses and common lightning tools via your LLM, providing Lightning Network functionality through natural language.

Enables file reading with pagination and regex-based code search across a codebase using grep.

A throwaway Docker sandbox for agents to run code and shell commands safely.

A Rust + Tauri 2 desktop application that turns local project folders into persistent MCP workspaces, enabling AI agents to read files, modify code, run commands and tests, check Git status, and maintain cross-conversation development context through historical checkpoints, with built-in WSS/FRP/Cloudflare tunnels and OAuth for connecting to ChatGPT.

A local MCP server that gives AI coding assistants read, write, search, and execute capabilities within a specified project directory. This Windows GUI build simplifies setup by eliminating manual Python, Node.js, or Docker installation.

A lightweight MCP server for managing DNS records, purging cache, and interacting with the Cloudflare API through natural language commands.