{"free":true,"payment_initiated":false,"method":"POST","purpose":"No-spend product quote and structural input validation before entering the x402 payment flow.","body":{"product_id":"decision-bundle","input":{"subject":"example","observed_at":"2026-09-07T08:00:00Z","values":[100,101,99,102,103,101,104,105,103,106,107,108]}},"note":"GET documents the free quote surface. POST performs schema-only validation and never signs or settles a payment."}