NotaryOS – Cryptographic proof of what your AI agent chose not to do

NotaryOS issues cryptographic receipts for AI agent actions — and non-actions. When an agent considers actions {A, B, C} and picks A, a "counterfactual receipt" proves B and C were evaluated and rejected at time T. Ed25519 signed, SHA-256 hash-chained, append-only. You can't backdate, reorder, or delete entries without breaking the chain. Verify any receipt offline, no auth needed.

I built this by accident. I started with a proprietary agent-to-agent protocol because I wanted secure multi-agent communication — 7-layer zero-trust, sub-3ms P50 latency, 1,100+ RPS. The protocol worked better than expected, and I realized the receipts it generated were themselves useful. So I built NotaryOS on top of it.

The obvious limitation: agents self-report their non-actions today. Same trust model as git — the author commits, the DAG enforces integrity. I'm building external verification via commit-reveal protocol, which is partly why this is a beta. The other reason: 350+ unique clones on the repo, zero stars, and I've started seeing "counterfactual receipts" referenced online. Things move fast in the agent space — I'd rather ship early than ship perfect.

I have no social media presence and I'm not in the tech industry. I don't know how to market this. HN seemed like the right place. If you have feedback on the idea, the API design, or advice on where to take this — I'm genuinely asking.

For anyone curious about the underlying A2A protocol (the backend that powers this), happy to share more about the architecture. It's a separate proprietary system, but the design decisions around zero-trust agent communication and low-latency message routing might be interesting on their own.

Try it (no account needed):

curl -s https://api.agenttownsquare.com/v1/notary/sample-receipt | python3 -m json.tool

pip install notaryos npm install notaryos

Verification is always free. Public key at /.well-known/jwks.json.

GitHub: https://github.com/hellothere012/notaryos Live: https://notaryos.org

Contact Email: [email protected]