{"uid":"cap_9bscwu-k4Yb-qmdJ-x5K2","slug":"402sentinel-x402-counterparty-risk-firewall-28018b1c","name":"402Sentinel x402 Counterparty Risk Firewall","description":"Buyer-side payment firewall: should THIS agent make THIS payment now? Where /api/assess vets the seller, this vets the payment against your own agent's behaviour. POST {agent_id, payment:{payto_address,amount,resource_url}, context?:{untrusted_text,intended}, policy?} returns allow/hold/block plus 9 signals incl. routing_anomaly, velocity, amount_anomaly, injection_destination, intent_mismatch. Stateful per agent_id.","url":"https://402sentinel.com/api/firewall","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"policy":{"type":"object","description":"Optional checks, e.g. {check_counterparty: true}."},"context":{"type":"object","properties":{"source":{"type":"string","description":"e.g. \"tool_output\", \"web_content\"."},"metadata":{"type":"object"},"expected_payto":{"type":"string","description":"The payTo the agent intended, to detect routing swaps."}},"description":"Where the payment instruction came from (provenance)."},"payment":{"type":"object","required":["payto_address"],"properties":{"asset":{"type":"string","description":"e.g. \"USDC\""},"amount":{"type":"number"},"resource_url":{"type":"string","description":"The resource being paid for."},"payto_address":{"type":"string","description":"Address the payment would go to — 0x EVM (Base) OR base58 Solana."}},"description":"The payment instruction being vetted."},"agent_id":{"type":"string","description":"The calling agent's wallet (keys per-agent history). Optional — auto-filled from the x402 payer if omitted."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_hRASO4K99L7yIjXlIoHiy","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Scores an x402 payment counterparty address (0-100 risk) and returns an allow/review/block decision based on on-chain settlement behaviour before payment is made","exampleAgentPrompt":"Before I pay this x402 API, run a counterparty risk check on the address 0xAbC123... and tell me whether I should allow, review, or block the payment based on its on-chain settlement history.","exampleUseCases":[{"title":"Validate vendor before automated USDC payments","prompt":"I'm about to set up recurring micropayments to this service provider's x402 address on Base. Can you quickly check if they're legitimate and safe to pay based on their on-chain history, and let me know if I should allow it or flag it for review first?"},{"title":"Screen suspicious payment endpoint for fraud","prompt":"An agent just tried to pay this unknown x402 endpoint that popped up in our workflow. Run a risk check on that address and tell me if it looks legitimate or if we should block it — I'm worried it might be a scam endpoint trying to intercept our payments."},{"title":"Gate RWA token transfers to trusted counterparties","prompt":"Before my agent transfers this tokenized asset to a buyer's x402 address, verify they're a legitimate counterparty and not flagged for sanctions or structuring issues. Give me the risk score and your recommendation on whether we should proceed."}],"resultDescription":"A JSON response containing a 0-100 risk score and a categorical decision of allow, review, or block, derived from on-chain signals including address age, facilitator-aware payer diversity, and settlement maturity for the queried counterparty address.","failureModes":["Address not found on-chain — insufficient history to score, may return a default high-risk or indeterminate result","Invalid or malformed address input — 400 error","Payment for the x402 call itself fails or is rejected — service not invoked","Network congestion on Base causing delayed settlement verification","New address with zero history — may default to block or review due to lack of data"],"whenToPreferThis":"Use this endpoint when an AI agent is about to make an x402 micropayment and needs a pre-flight counterparty risk check based purely on on-chain settlement behaviour. Prefer this over generic blockchain analytics when you specifically need x402-aware payer diversity signals and a structured allow/review/block decision without any signup or API key.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T00:35:43.288Z","isFirstParty":false}