20 free checks per day. Then 0.005 USDC over x402.
Four layers, four different questions: is the form right?
is there anything inside it? what conditions produced it? was the action
permitted? Each layer answers only its own question and never substitutes
for the others.
1. Artifact — form and emptiness
2. Generation conditions
3. Authority — the mandate
4. Signature — verify it yourself
Ed25519: the public key
travels with the attestation. Verification needs neither our service nor a
secret.