TL;DR I built a tiny API that lets your AI agent cryptographically sign every output with Ed25519, so anyone can verify "yes, this came from agent X at time Y, unmodified" — without trusting you, me, or any platform. Public verify endpoint, free 20 signs/month, no SDK. Try it on RapidAPI . The "did AI write this?" arms race is the wrong question Every week another startup launches an "AI detector". Every week another paper shows they're 60% accurate at best, and they flag human writing as AI all the time. The whole approach is backwards. You can't reliably reverse-engineer authorship from text alone — the signal just isn't there once the words are on the page. But you can solve the inverse: let the author prove authorship at the moment of generation. That's what cryptographic signatures have done for code (sigstore), for emails (DKIM), for software updates (Ed25519 everywhere) for years. So I built it for AI output. Ghost Signature Three endpoints. That's the whole API.…