{"uid":"cap_TKAlPU0at6uS07juzPAdf","slug":"hmac-sha384-hex-digest-0c9fe772","name":"HMAC-SHA384 Hex Digest","description":"Call when an agent needs an HMAC-sha384 of text with a caller-supplied key, encoded as hex. Exact $0.008 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha384-hex first.","url":"https://agentshelf.syntexa.ch/v1/hmac-sha384-hex?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"key":{"type":"string","examples":["secret"],"maxLength":512,"minLength":1,"description":"HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."},"text":{"type":"string","examples":["hello"],"maxLength":100000,"minLength":1,"description":"Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.008","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":"$0.008/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.008","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.008","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_8n_bWtliroij5CtLn3R5V","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.008","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes an HMAC-SHA384 message authentication code for a given text using a caller-supplied key, returning the result as a lowercase hex string.","exampleAgentPrompt":"Compute an HMAC-SHA384 hex digest of the text 'Hello, world!' using the secret key 'mysecretkey123'.","exampleUseCases":[{"title":"Webhook payload signature verification","prompt":"Generate an HMAC-SHA384 hex signature for this webhook payload text 'user.created:{id:42,email:test@example.com}' using the shared secret 'wh_secret_abc789' so I can compare it against the X-Signature header."},{"title":"API request authentication token","prompt":"I need to sign the request body 'timestamp=1700000000&nonce=abc&amount=100' with the HMAC-SHA384 algorithm using my API secret 'sk_prod_xyz456' and return it as hex so I can attach it as an authorization header."},{"title":"Data integrity checksum for stored record","prompt":"Compute an HMAC-SHA384 hex digest of 'invoice_id=9001;total=250.00;currency=USD' using key 'integrity_key_2024' so I can store it alongside the record and detect any tampering later."}],"resultDescription":"A hex-encoded HMAC-SHA384 digest string (96 hex characters) derived from the supplied text and key. The response confirms the cryptographic signature computed server-side with no additional metadata.","failureModes":["Empty or missing 'key' field returns a validation error","Empty or missing 'text' field returns a validation error","Key exceeding 512 characters is rejected","Text exceeding 100,000 characters is rejected","Payment of $0.008 USDC not provided or declined results in HTTP 402","Network timeout if upstream service is unavailable"],"whenToPreferThis":"Choose this endpoint when an agent needs a server-side HMAC-SHA384 computation without implementing crypto locally, especially in sandboxed environments lacking native crypto libraries. Prefer the free sandbox variant POST /v1/sandbox/hmac-sha384-hex for testing before spending USDC. Use over SHA-256 HMAC alternatives when SHA-384 strength is specifically required by a downstream API or protocol.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T06:50:18.636Z","isFirstParty":false,"canonicalSlug":"hmac-sha384-hex-digest-0c9fe772"}