{"uid":"cap_wt4UL9Py_Fd812ToEVt21","slug":"signalharness-abi-signature-selector-4d7bbb20","name":"SignalHarness ABI Signature Selector","description":"Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.","url":"https://signalharness.ai/api/agent/services/abi_signature_selector/invoke","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"abi_signature_request":{"type":"string","maxLength":65536,"minLength":2}}},"responseSchema":{"type":"json","example":{"replay":false,"result":{"warnings":["Selectors alone do not prove an interface is implemented."],"service_id":"abi_signature_selector","evidence_scope":"caller_supplied_data","signature_selectors":"{\"kind\":\"function\",\"selectors\":[{\"selector\":\"0x70a08231\",\"signature\":\"balanceOf(address)\"},{\"selector\":\"0xa9059cbb\",\"signature\":\"transfer(address,uint256)\"}]}"},"status":"succeeded","receipt":{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","usage":[],"status":"succeeded","network":"eip155:8453","artifacts":[],"endedAtMs":0,"latencyMs":0,"paymentId":"example-payment","receiptId":"example-receipt","requestId":"example-request","serviceId":"abi_signature_selector","executionId":"example-execution","startedAtMs":0,"amountAtomic":"5000","resultSha256":"2985fc2ce0e1ecaffce7ea49fbebe23b6adda9e99e9042990c1b32bda229d377","serviceVersion":"1.0.0","settlementReference":"0x0000000000000000000000000000000000000000000000000000000000000000"},"artifacts":[],"requestId":"example-request","executionId":"example-execution"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","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":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_9u77xU1Y6PpkOEzdtXb7K","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Resolves and returns ABI function/event signature selectors for a given Solidity ABI signature request string","exampleAgentPrompt":"What's the 4-byte ABI selector for the Solidity function signature `transfer(address,uint256)`? I need the hex selector I can use when building a raw EVM calldata payload.","exampleUseCases":[{"title":"Resolve ERC20 function selector","prompt":"Can you look up the ABI signature selector for `approve(address,uint256)` so I can construct the correct calldata for an ERC20 approve transaction?"},{"title":"Identify event topic hash","prompt":"I need the keccak256 topic hash for the Solidity event `Transfer(address,address,uint256)` — can you resolve the ABI signature selector for it?"},{"title":"Validate unknown calldata prefix","prompt":"I'm seeing a 4-byte prefix of `0xa9059cbb` in some raw transaction calldata — can you confirm what ABI function signature that selector corresponds to?"}],"resultDescription":"Returns a JSON object with a `signature_selectors` field containing the resolved hex selector(s) for the provided ABI signature, along with any `warnings` about ambiguity or issues, the `service_id`, and `evidence_scope`. Also includes a full payment receipt with timing, payment ID, amount, network (Base), and a SHA256 hash of the result for verification.","failureModes":["Malformed or syntactically invalid ABI signature string returns error or empty selectors","Ambiguous overloaded signatures may produce warnings","Input string exceeding 65536 characters is rejected by schema validation","Network or payment processing failure returns non-succeeded status","Unknown or non-standard signature not in known databases may return no match"],"whenToPreferThis":"Choose this endpoint when you need a fast, reliable resolution of Solidity ABI function or event signature selectors without running a local Ethereum node or relying on free public databases that may be incomplete. It is priced per-call at $0.005 USDC via x402 micropayment, making it suitable for agent workflows that need on-demand selector resolution without bulk subscription commitments.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T13:07:22.197Z","isFirstParty":false}