captcha-mcp

stdiononeother

L402 Lightning paywall and PoW gate for MCP tool calls. Free tier solves a Hashcash challenge; paid tier pays a Lightning invoice via self-hosted LNBits. No accounts, no API keys.

github ↗

Install

How to run this server

[ { "cmd": "npx -y @powforge/captcha-mcp", "imports": [] } ]

server path: captcha-mcp

Tools

What this server exposes

challenge

Request a fresh proof-of-work puzzle. Returns {id, salt, difficulty, signature}.

verify

Submit a solved nonce. Returns a 5-minute HMAC-signed access token.

status

Server health, lifetime stats, L402 endpoint metadata.

Configuration

Environment & auth

authnone

envCAPTCHA_URL

Resources

githubhttps://github.com/zekebuilds-lab/captcha-mcp ↗