{"name":"onyx_x402_simulate","tier":"free","price_usdc":"0","endpoint":"https://onyx-actions.onrender.com/v1/onyx_x402_simulate","method":"POST","input_schema":{"type":"object","properties":{"endpoint_url":{"type":"string","description":"Full URL of the paid endpoint to simulate against (e.g. https://onyx-actions.onrender.com/v1/onyx_aml_screen)."},"method":{"type":"string","enum":["GET","POST"],"default":"GET","description":"GET hits the introspection card (works even on unpaid endpoints); POST hits the live 402 challenge (works on every paid endpoint)."},"signer_address":{"type":"string","description":"Address that would sign the EIP-3009 authorization. Used to fill the 'from' field in the template payment payload. Optional — defaults to 0x0...01."}},"required":["endpoint_url"]},"description":"Simulate an x402 v2 payment flow against any paid endpoint. Fetches the 402 challenge (or introspection card), parses paymentRequirements, generates a template X-PAYMENT payload with the exact fields an agent would need to sign (EIP-3009 authorization shape, validBefore window, asset address, recipient), and returns next-step guidance. Pure simulation — no keys, no signing, no payment. SSRF-hardened.","when_to_use":"An agent (or dev writing an x402 client) wants to see exactly what payment would be required for a given endpoint, including the EIP-3009 authorization fields and timing window, before committing wallet gas or signing.","vs_alternatives":"x402-fetch / @x402/fetch / x402-axios all wrap fetch and handle 402 automatically — they're for production. This tool is for inspection: it tells you what an x402 challenge says without signing or paying, and emits a ready-to-sign payload template. Pairs with onyx_verify_explain (diagnose after) for full client-side x402 dev coverage.","example_request":{"endpoint_url":"https://onyx-actions.onrender.com/v1/onyx_aml_screen","method":"POST","signer_address":"0xc0E92810f992b7EE487b5B9b6B7dB4a2A13249fe"},"example_response":{"ok":true,"endpoint_url":"https://onyx-actions.onrender.com/v1/onyx_aml_screen","method_used":"POST","fetch_status":402,"fetch_source":"header:payment-required","price_usdc":0.25,"network":"eip155:84532","pay_to":"0x4326acB1A35e6B744BaAeA850c702Ca71dF86Cd5","max_timeout_seconds":300,"next_steps":["1. Sign EIP-3009...","..."]},"settle_to":"0x3fD9ee1373562f894D322B37DFFAd7a5D2b2d78f","network":"base","facilitator":"https://facilitator.xpay.sh","payment_required":false,"free_introspection":true,"note":"GET this URL = free introspection card. POST with x402 payment header to call."}