Quote an x402-paid API before you buy: probes a third-party endpoint with one unpaid GET (no payment is ever sent) and decodes its payment requirements — x402 v2 base64 PAYMENT-REQUIRED header or v1 JSON body. Returns normalised prices (atomic amount, asset, network, payTo), description, resource URL and Bazaar discovery metadata. Non-402 targets return {isX402:false, status}. SSRF-checked, 1 redirect max, 8 s timeout.