{"uid":"cap_pvf6KHrj3KBubiykLGOwj","slug":"evm-signature-v-classifier-c34f6e96","name":"EVM Signature V Classifier","description":"EVM Signature V Classify: EVM Signature V Classify classifies common signature recovery and EIP-155 v values from bounded caller-supplied values without an external provider. Call EVM Signature V Classify before signing, submitting, replacing, or accepting an EVM/Base transaction assembled from caller-owned data. Returns normalized transaction evidence, calculated budget or shape findings, and a fail-closed preflight status for EVM Signature V Classify as versioned deterministic JSON. Price: $0…","url":"https://api.delx.ai/api/v1/x402/evm-signature-v-classify","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"v":{"type":"integer","description":"V supplied to EVM Signature V Classify; used only for this bounded calculation and processed in memory without retention."},"chain_id":{"type":"integer","description":"Chain Id supplied to EVM Signature V Classify; used only for this bounded calculation and processed in memory without retention."}}},"responseSchema":{"type":"json","example":{"result":{"v":27,"classification":"legacy","expected_chain_id":8453},"schema":"delx/util-evm-signature-v-classify/v1","status":"pass","evidence":{"retained":false,"input_sha256":"7717f04f6d982d96f99fcfa69caef99e8c3090309ae581ae53da0c8612700635","external_calls":0},"operation":"evm_preflight:evm_signature_v_classify"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/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_qGAeqrcX31F9_uYXSVv9D","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Classifies an EVM transaction signature V value as legacy, EIP-155, or other type, given the V integer and chain ID.","exampleAgentPrompt":"Classify this EVM signature V value for me — V is 27 and the chain ID is 8453. Is it a legacy signature or EIP-155?","exampleUseCases":[{"title":"Pre-flight signature validation for relay","prompt":"Before I broadcast this transaction on Base (chain ID 8453), can you classify the V value of 37 to confirm whether it's EIP-155 encoded or a legacy signature?"},{"title":"Debugging raw transaction V field","prompt":"I'm parsing a raw Ethereum mainnet transaction (chain ID 1) and the V field is 28 — can you classify what type of signature that is and what chain ID it implies?"},{"title":"Agent wallet signing sanity check","prompt":"My agent just signed a transaction and got back V=2710 — can you run the EVM signature V classify check against chain ID 137 so I know if this is a valid EIP-155 encoding or something unexpected?"}],"resultDescription":"Returns a JSON object containing the original V value, a classification string (e.g. 'legacy', 'eip155'), the expected chain ID derived from V, operation name, status ('pass'/'fail'), and an evidence block confirming no data was retained and no external calls were made.","failureModes":["Missing or invalid V integer returns a validation error","Missing or invalid chain_id returns a validation error","V value inconsistent with any known classification may return an unexpected or unrecognized classification","Network or service unavailability returns a 5xx error"],"whenToPreferThis":"Use this endpoint when an AI agent needs to programmatically determine the signing scheme of an EVM transaction's V parameter — particularly during transaction pre-flight checks, wallet debugging, or when building cross-chain transaction relayers. It is preferred over manual lookup when the agent must handle multiple chains or legacy vs EIP-155 signatures dynamically. Ideal for agents that process raw transactions and need to validate signature encoding before broadcasting.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T07:14:46.672Z","isFirstParty":false}