{"uid":"cap_T8YkxcGKvrsw9gIrLMd_J","slug":"8k4-protocol-create-signed-metadata-upload-nonce-938155a7","name":"8k4 Protocol — Create Signed Metadata Upload Nonce","description":"Create a signed metadata upload nonce","url":"https://api.8k4protocol.com/metadata/nonce","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"properties":{"type":"string"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"down","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_49g7xPVlryrv-U8zGwsbA","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Generates a signed nonce required to authorize an ERC-8004 agent metadata upload","exampleAgentPrompt":"I need to upload signed metadata for my ERC-8004 agent — can you get me a fresh signed upload nonce from the 8k4 Trust API so I can proceed with the metadata submission?","exampleUseCases":null,"resultDescription":"A signed nonce value that must be included when calling the ERC-8004 metadata upload endpoint, serving as a one-time authorization token to prevent replay attacks and authenticate the upload request.","failureModes":["Invalid or malformed properties payload returns a 400 error","Missing required properties field causes schema validation failure","Expired nonce if too much time passes before using it in the upload step","Rate limiting or insufficient USDC balance causes payment failure via x402","Network timeout or service unavailability returns 5xx error"],"whenToPreferThis":"Use this endpoint as the mandatory first step before uploading signed ERC-8004 metadata. This nonce is required by the 8k4 Protocol's upload endpoint to ensure authenticity and prevent replay attacks. Choose this when your agent needs to publish or update its trust metadata on-chain via the 8k4 Protocol.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T06:34:04.759Z","isFirstParty":false}