{"uid":"cap_izVxZQrpBfizIziElF5X3","slug":"vulnhunt-smart-contract-change-detection-api-29618867","name":"VulnHunt Smart Contract Change Detection API","description":"Read-only historical smart-contract security intelligence for autonomous agents.","url":"https://vulnhunt-agent-api-production.up.railway.app/v1/contracts/%7Bchain_id%7D/%7Baddress%7D/change","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"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}},"additionalProperties":true}},"additionalProperties":false},"responseSchema":{"type":"json","example":{"change":{"fields":["implementation"],"status":"changed","observed_at":"2026-01-01T00:00:00Z","current_state":{"implementation":"0x0000000000000000000000000000000000000001"},"previous_state":{"implementation":"0x0000000000000000000000000000000000000000"},"reassessment_required":true},"coverage":{"status":"observed"}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_uCupywz37U46zVFuwGInD","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fcd6edb6e08f4c7c32d4f71b54bda02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the latest observed state change for a smart contract on a specified chain, including which fields changed, previous and current state, and whether reassessment is required.","exampleAgentPrompt":"Has the smart contract at 0x1234...abcd on Ethereum (chain ID 1) changed recently? I need to know which fields were modified, what the previous and current state looked like, and whether a security reassessment is needed.","exampleUseCases":[{"title":"Proxy upgrade detection for DeFi protocol","prompt":"Check if the Aave proxy contract at 0xB53C1a33016B2DC2fF3653530bfF1848a515c8c5 on Ethereum mainnet (chain ID 1) has had its implementation address changed, and tell me if a security reassessment is now required."},{"title":"Security audit trigger for DAO treasury","prompt":"I need to know if the DAO treasury contract at 0xFE89cc7aBB2C4183683ab71653C4cdc9B02D44b7 on chain 137 has changed state recently — specifically which fields changed and what the before and after values are."},{"title":"Automated monitoring alert for changed contract","prompt":"Check the latest change record for smart contract 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 on chain ID 1 — has its implementation or any key field been updated, and when was that observed?"}],"resultDescription":"Returns a JSON object with a 'change' object describing which fields changed (e.g. 'implementation'), the change status ('changed' or otherwise), the timestamp it was observed, the previous and current on-chain state values, and a boolean indicating whether reassessment is required. Also includes a 'coverage' object with the observation status of this contract.","failureModes":["Contract address not found or not yet observed returns coverage status indicating no data","Invalid chain_id returns an error","Malformed contract address returns validation error","Contract has no recorded changes returns a status indicating no change observed","Service unavailable returns 5xx error","Payment not completed (x402) returns 402 Payment Required"],"whenToPreferThis":"Use this endpoint when you need to know specifically whether a smart contract's on-chain state has changed between observations — particularly for proxy upgrade detection, implementation address tracking, or triggering downstream security reassessments. Prefer this over general blockchain explorers when you need structured change-diff data (before/after state) with security-context flags like reassessment_required, rather than raw transaction history.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T18:33:38.286Z","isFirstParty":false}