Side-by-side comparison of two Model Context Protocol servers — install paths, tools, quality signals, and directory engagement so you can pick the right one for Claude, Cursor, and other MCP clients.
L402 Lightning paywall + Hashcash proof-of-work gate for MCP tool calls. Free tier solves a PoW challenge; paid tier pays a Lightning invoice via self-hosted LNBits. No accounts, no API keys, no third-party SaaS. Drop-in middleware for any MCP server. npx @powforge/captcha-mcp.
Human sign-off + trust receipts for AI agents: requires a named human's approval before an irreversible action (payment release, record change, deploy), then mints an offline-verifiable Ed25519 Trust Receipt. Also exposes trust profiles, receipt verification, disputes, and delegation. Apache-2.0; policy engine formally verified. Install: npx -y @emilia-protocol/mcp-server.