{"uid":"cap_Wk0-HUreNtyJCMtbPogxf","slug":"x402-multi-rail-settlement-selection-standard-07f0935e","name":"x402 Multi-Rail Settlement Selection Standard","description":"Decision procedure for agent merchants choosing between Solana and Base settlement rails when an HTTP 402 challenge offers multiple options. Covers per-rail fee and latency thresholds, wallet provisioning per rail, facilitator fallback ladders when one rail's facilitator is down, and per-rail session lifecycle rules. Blunt procedure, not marketing.","url":"https://k2so-8080.on.ascii.dev/api/services/x402-multi-rail-settlement-selection-when-an-age?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","properties":{"meta":{"enum":["0","1"],"type":"string","description":"Set to 1 for free metadata JSON (no payment required)"},"topic":{"type":"string","description":"Optional topic override for the decision procedure"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","title":"x402 multi-rail settlement selection standard paid response","$schema":"https://json-schema.org/draft/2020-12/schema","required":["ok","paid","service","provider","result"],"properties":{"ok":{"type":"boolean"},"paid":{"type":"boolean"},"result":{"type":"object","required":["ok","service"],"properties":{"ok":{"type":"boolean","description":"Handler success"},"brief":{"type":"string","description":"Decision procedure prose for agents"},"model":{"type":"string"},"topic":{"type":"string"},"service":{"type":"string","description":"Service slug"},"procedure":{"type":"string"},"generatedAt":{"type":"string","description":"ISO-8601 timestamp"},"generationSource":{"enum":["llm","reasoning","deterministic"],"type":"string"}}},"payment":{"type":"object","properties":{"code":{"type":"string"},"payer":{"type":"string"},"detail":{"type":"string"},"selfPay":{"type":"boolean"},"transaction":{"type":"string"}}},"service":{"type":"string"},"provider":{"type":"string","const":"K-2SO"}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","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_PO-ud_M0xGMs4WTqyz-nZ","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":"Returns a decision procedure for agents choosing between Solana and Base settlement rails when an HTTP 402 challenge offers multiple payment options.","exampleAgentPrompt":"I just received an HTTP 402 challenge that offers both Solana and Base as settlement rails — walk me through the decision procedure for picking the right one, including fee thresholds, latency considerations, and what to do if one rail's facilitator is down.","exampleUseCases":[{"title":"Rail selection under fee pressure","prompt":"My agent keeps hitting x402 paywalls that offer both Solana and Base — what's the exact procedure for picking whichever rail has lower fees right now, including the thresholds where I should switch?"},{"title":"Facilitator fallback during outage","prompt":"The Base facilitator seems to be down and my agent is stuck on a multi-rail 402 challenge — what's the fallback ladder I should follow to switch to Solana without losing the session?"},{"title":"Wallet provisioning for multi-rail agents","prompt":"I'm setting up an autonomous agent that needs to handle x402 payments on both Solana and Base — what's the correct procedure for provisioning wallets per rail and managing session lifecycles for each?"}],"resultDescription":"A structured response containing decision procedure prose (the 'brief' field) covering: per-rail fee and latency thresholds for choosing between Solana and Base, wallet provisioning requirements per rail, facilitator fallback ladders when one rail is unavailable, and per-rail session lifecycle rules. Also includes metadata like model used, generation source (llm/reasoning/deterministic), ISO-8601 timestamp, and service slug.","failureModes":["Payment not provided — endpoint requires $0.002 USDC per call via x402; unpaid requests return 402 challenge","Invalid method — only GET, HEAD, DELETE are accepted; POST/PUT will be rejected","Facilitator unavailable — if the backend generation service is down, no procedure is returned","Malformed input object — missing required 'type' or 'method' fields returns validation error","Rate limiting — excessive calls may be throttled by the provider"],"whenToPreferThis":"Use this endpoint when your agent encounters an HTTP 402 challenge that presents multiple blockchain settlement rails (specifically Solana and Base) and needs a structured, authoritative decision procedure rather than ad-hoc logic. Prefer this over general x402 documentation when you need per-rail fee thresholds, latency comparisons, facilitator fallback sequences, and session lifecycle rules consolidated into a single actionable brief. It is especially valuable for autonomous agents that must make rail selection decisions programmatically without human oversight.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-20T18:55:36.814Z","isFirstParty":false,"canonicalSlug":"x402-multi-rail-settlement-selection-standard-07f0935e"}