30 seconds, end-to-end
What you just saw
Beat 1 — chat free. The agent introduces itself; the page suggests a few one-tap prompts. Nothing has cost anything yet.
Beat 2 — quote the price. You ask for an aura check on Elon Musk. The agent says it’ll run aura for $0.01 and shows an approval card with the exact endpoint (POST /v1/aura), the input (Elon Musk), and the cost in USDC.
Beat 3 — connect. Tap connect. A Coinbase Smart Wallet popup appears. Touch ID / Face ID creates a passkey-based wallet in your browser — no app install, no seed phrase, no email. The wallet is non-custodial and bound to your device.
Beat 4 — approve. The button relabels to approve $0.010. Tap again. Your wallet signs one EIP-3009 USDC transferWithAuthorization for exactly that amount, to exactly the anchor-x402 treasury, on Base mainnet. The Coinbase CDP facilitator settles the payment; gas is on them.
Beat 5 — the result. Aura returns a color, a tier (S → F), a 0–9999 score, and a punchy description. The agent translates the JSON into natural language. Your spend pill in the corner ticks up to $0.010 / $5.00.
What you didn’t see
- An account creation form. There isn’t one.
- An API key. None required.
- A subscription. Nothing recurring.
- A custodial wallet. Your private key lives in your device’s secure enclave.
Each paid call is its own EIP-3009 signature for a single amount to a single address — there is no standing approval, no “agent burns through your wallet while you sleep” failure mode.
15 services in this same flow
aura ($0.01) is one of fifteen. Same approval pattern works for:
- Compliance — OFAC sanctions screen ($0.001), bundled wallet intel ($0.005), full async due-diligence investigator ($7.77)
- Chain utilities — dual-chain hash anchoring ($0.005), signed decision attestations ($0.01), tx decode, calldata decode, ENS / SNS resolution, token price, datetime parsing ($0.001 each)
- Fun / shareable — roast ($0.05), oracle with on-chain anchored verdict ($0.05), tldr ($0.01), aura ($0.01), grade ($0.01)
All on the same Lambda, same x402 v2 protocol, same CDP facilitator. The MCP server anchor-x402-mcp gives any agent (Claude Desktop / Cursor / Codex / ChatGPT Desktop) the same 14 tools (everything except the async investigator and the hosted chat surface).
Specifically for the wallet-curious
- Protocol: x402 v2, payment requirements in the
payment-requiredresponse header, EIP-3009transferWithAuthorizationsettlement on Base or SPL-USDC on Solana - Facilitator: official Coinbase CDP (
api.cdp.coinbase.com/platform/v2/x402), which handles ERC-6492 unwrapping so smart-wallet signatures verify correctly - Treasury:
0x127462e296fAc1A7F5cF33bA57bB2f0FFf5cD0B6— on-chain receipts are independent of the service - Source: MIT-licensed — fork it, audit it, deploy your own
The full security posture lives at /trust/ — STRIDE threat model, SIG-Lite questionnaire, regulated deployment guide.
Bring USDC on Base. Cheapest call is $0.001.