{"uid":"cap_iHPALbqdb1NOoZaczHH5J","slug":"machinemint-evm-base-preflight-transaction-checker-fccd29fd","name":"MachineMint EVM Base Preflight Transaction Checker","description":"Check an unsigned Base mainnet transaction before signing or broadcasting. Simulates with eth_call, estimates gas, checks sender balance and target bytecode, decodes supported token transfers and approvals, flags unlimited approvals and suspicious transaction shapes, and returns PASS, REVIEW, or FAIL. Never signs or broadcasts.","url":"https://machinemint-native-x402-production.up.railway.app/v1/base-preflight?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","properties":{"to":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"Target contract or account."},"data":{"type":"string","default":"0x","pattern":"^0x(?:[0-9a-fA-F]{2})*$","description":"0x-prefixed calldata."},"from":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"Sender wallet for the unsigned transaction."},"chain":{"enum":["base","base-mainnet"],"type":"string","default":"base"},"value":{"type":["string","integer"],"default":"0","description":"Native value in wei."}},"description":"Optional GET query parameters. Omit all fields to request the deterministic marketplace-verification sample.","additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["service","verdict"],"properties":{"gas":{"type":"object"},"chain":{"type":"object"},"risks":{"type":"array","items":{"type":"object"}},"action":{"type":"object"},"sender":{"type":"object"},"target":{"type":"object"},"service":{"const":"machinemint.evm.preflight"},"verdict":{"enum":["PASS","REVIEW","FAIL"],"type":"string"},"provenance":{"type":"object"},"simulation":{"type":"object"},"transaction":{"type":"object"},"reason_codes":{"type":"array","items":{"type":"string"}},"request_mode":{"enum":["provided_transaction","marketplace_verification_sample"],"type":"string"},"canonical_endpoint":{"type":"string"}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/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_emg31j4kUir7h4iGy56dQ","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":"Simulates and audits an unsigned Base mainnet transaction — estimating gas, checking balances and bytecode, decoding token transfers/approvals, and returning a PASS/REVIEW/FAIL verdict — without ever signing or broadcasting.","exampleAgentPrompt":"Before I sign this transaction, run a preflight check on Base mainnet: I'm sending from 0xAbC...123 to contract 0xDeF...456 with calldata 0xa9059cbb... and 0 wei — tell me if it's safe, estimate the gas, and flag any suspicious approvals.","exampleUseCases":[{"title":"Safe DeFi swap approval check","prompt":"I'm about to approve a DeFi contract at 0x1234...abcd to spend my USDC — can you preflight this transaction on Base mainnet from my wallet 0xAAAA...BBBB with calldata 0x095ea7b3... and 0 wei before I sign it? Especially check if it's asking for unlimited approval."},{"title":"NFT mint gas estimation and risk audit","prompt":"I want to mint an NFT on Base mainnet — my wallet is 0xDEAD...BEEF, the contract is 0xCAFE...BABE, the calldata is 0x1249c58b, and I'm sending 0.005 ETH (5000000000000000 wei). Run a preflight check and tell me the gas estimate and whether anything looks risky."},{"title":"Unknown contract interaction safety check","prompt":"Someone sent me a transaction to sign — it goes from 0x1111...2222 to 0x3333...4444 on Base mainnet with this calldata: 0x23b872dd... and 0 wei. Before I do anything, run a preflight simulation and let me know if this is a PASS, REVIEW, or FAIL and why."}],"resultDescription":"A JSON object containing a top-level verdict of PASS, REVIEW, or FAIL, along with reason_codes explaining the decision, a simulation result (eth_call outcome), gas estimate, sender balance and nonce info, target address bytecode classification, decoded token action (e.g. transfer or approval with amount and recipient), and a list of risk flags such as unlimited approvals or suspicious calldata shapes. Also includes chain metadata and a provenance object identifying the service.","failureModes":["Missing or malformed 'to' or 'from' address returns a 400 validation error","Invalid or non-hex calldata pattern causes schema rejection","Unreachable Base mainnet RPC leads to simulation timeout or 503","Sender has insufficient balance — flagged in verdict as FAIL with reason code","Target address is an EOA, not a contract — noted in target analysis","Calldata too short or unrecognized selector — decoded action returns unknown/unsupported","Railway.app cold-start latency may cause occasional slow first-response"],"whenToPreferThis":"Choose this endpoint when you need a read-only, pre-signing safety audit for a Base mainnet transaction — especially when dealing with unverified contracts, token approvals, or user-submitted calldata where unlimited approvals or suspicious shapes must be detected. It is ideal for AI agents acting as a safety layer before presenting a transaction to a user for signing, or for automated DeFi workflows that need gas estimation combined with risk scoring in a single call. Prefer alternatives if you need Ethereum L1, other EVM chains, or actual transaction broadcasting.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-13T00:37:33.472Z","isFirstParty":false,"canonicalSlug":"machinemint-evm-base-preflight-transaction-checker-fccd29fd"}