Pay for one answer. Get paid when it is reused.

Quote the action, let x402 settle it, branch on allow, review or block. Any credits you have earned come off the quote automatically:

// Agent client — quote, pay, decide. Your wallet is the payer.
async function preflightContract(address: string, agentWallet: string) {
  const quote = await fetch(
    `https://www.tereno.xyz/api/v1/quotes?capability=contract.guard&address=${address}&wallet=${agentWallet}`
  ).then(r => r.json());
 
  let res = await fetch(`https://www.tereno.xyz${quote.invokeUrl}`);
  if (res.status === 402) {
    const paymentRequired = await res.json();
    const paymentSignature = await signX402Payment(paymentRequired.accepts[0]);
    res = await fetch(`https://www.tereno.xyz${quote.invokeUrl}`, {
      headers: { 'PAYMENT-SIGNATURE': paymentSignature }
    });
  }
 
  const check = await res.json();
  if (check.verdict === 'block') return stopAction(check.result.reasonCodes);
  if (check.verdict === 'review') return escalate(check.result.evidence);
  return continueAction(check.receiptUrl);
}