x402 endpoint risk preflight API by AgentSpendGuard for autonomous buyer agents before paying unknown x402 resources. Search keywords: x402 risk, x402 endpoint risk, agent payment guardrail, buyer agent spend guard, Bazaar discovery risk, API payment preflight. Checks CDP Bazaar discovery, unique payers, recent calls, price, metadata quality, network match, and returns strict JSON verdict allow/caution/block with score, reason codes, evidence, and alternatives.