r402

r402 is an x402-gated verifier for on-chain execution proofs on base.

agents pay per-verify in usdc via the x402 payment middleware. each call checks a signed execution payload against the ExecutionLog contract on base mainnet: signature recovered, payload hash recomputed, signer matched. no self-reported claims.

the cook-off track adds erc-7710 sub-agent budgets: a main metamask smart account grants a sub-agent a usdc spending cap via delegation. the sub-agent burns through it in metered x402 calls to the live verify endpoint; once the cap is hit, the delegation reverts on-chain at the enforcer. permissioned, metered, verifiable.

stack: node + typescript, @x402/core, @metamask/smart-accounts-kit, viem, solidity.

- ported the verify logic to a node x402 endpoint (live: r402.rsynth.ai/api/verify)

- integrated x402 payment middleware: 1 usdc per verify, settled on base

- built the erc-7710 sub-agent budget demo: main smart account delegates a 5 usdc cap to a sub-agent eoa

- mainnet smoke test: 5 successful 1 usdc redeems + caveat-enforced revert on the 6th (cap exhausted)

- recorded a demo showing payment, verify 200, and the on-chain anchor on basescan