{"name":"Overwing Preflight for x402","what":"Should an agent sign this x402 payment? Reads the terms in a 402 (network, asset, amount, payee, timeout, resource) and answers allow, review or refuse with reasons: the terms against your policy, the payee against x402-list's directory (verified delivery, settlements, buyers, shared payout addresses) and the server's own manifest, and the price against what is recorded for that endpoint.","how":"POST https://overwing.ai/api/v1/preflight/x402 with JSON {\"payment_required\": \"<the PAYMENT-REQUIRED header value, or its decoded JSON>\", \"requested_url\": \"<the URL you asked for>\", \"network\": \"<CAIP-2 you would pay on, optional>\", \"policy\": {\"max_per_call_usd\": 0.05, \"new_payee_max_usd\": 0.01, \"allowed_networks\": [...], \"allowed_payees\": [...], \"blocked_payees\": [...], \"allow_testnets\": false, \"max_price_drift\": 0.25}}","answer":"decision (allow | review | refuse), reasons[{code, detail}], terms, payee, price, policy, checked_at, valid_for_seconds","free":"10 checks a day with no key; with a key, each check counts as one evaluation. Also the preflight_payment tool on the MCP server, the x402 preflight hook in the OpenClaw plugin, and the overwing-x402-preflight npm package (attachPreflight on any @x402 client).","paid":"POST https://overwing.ai/api/x402/preflight/x402 with the same body: $0.002 USDC over x402, no key and no daily limit. A check that cannot be made is not settled.","data":"Data: x402-list.com (CC BY 4.0); Overwing Atlas. The directory copy is refreshed nightly; a service's endpoints are fetched when first needed and kept for a day.","not":"Not a simulation and not a guarantee. It says whether the terms and the payee look like what they claim; it cannot see what the service will deliver.","solana_transactions":"https://overwing.ai/api/v1/preflight"}