{"uid":"cap_8ZjLvgQISjq7c3nvLFZH5","slug":"evm-transaction-preflight-for-agents-286c6c4f","name":"EVM Transaction Preflight for Agents","description":"EVM transaction preflight modeled on top-earning tx simulator/explainer endpoints: decode target/value/data shape, probe bytecode, flag approvals/transfer selectors, and return sign/avoid/manual-review verdict. Price 0.15 USDC on Base via x402. Demo: https://x402-market-intel-mcp.mtree.workers.dev/demo/tx_preflight_for_agents. Contact: https://x402-market-intel-mcp.mtree.workers.dev/contact.","url":"https://x402-market-intel-mcp.mtree.workers.dev/v1/x402/tx_preflight_for_agents","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","bodyType","body"],"properties":{"body":{"type":"object","properties":{"to":{"type":"string"},"tx":{"type":"object"},"data":{"type":"string"},"chain":{"type":"string"},"value":{"type":"string"},"rpc_url":{"type":"string"}}},"type":{"type":"string","const":"http"},"method":{"enum":["POST"],"type":"string"},"bodyType":{"enum":["json","form-data","text"],"type":"string"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.15","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","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":"$0.15/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.15","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.15","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_SGHPV_YioeN8glLiXsblX","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.15","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Decodes and analyzes an EVM transaction (target, value, calldata) to flag approvals, transfer selectors, and bytecode risk, returning a sign/avoid/manual-review verdict before the agent submits it on-chain.","exampleAgentPrompt":"Before I submit this transaction, run a preflight check on it: the target contract is 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, value is 0, and the calldata is 0x095ea7b3000000000000000000000000someSpenderAddress000000000000000000000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff — tell me if I should sign, avoid, or manually review it.","exampleUseCases":[{"title":"Review token approval before signing","prompt":"I'm about to approve a token spend for a DeFi protocol. Can you decode this transaction and tell me if it's safe to sign? Target is 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, value is 0, and calldata is 0x095ea7b3000000000000000000000000spenderaddress000000000000000000000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff — what's your verdict?"},{"title":"Preflight check suspicious contract interaction","prompt":"My agent is about to submit a contract call but I want to verify it first. The target contract is 0x1234567890123456789012345678901234567890, the value being sent is 0, and the calldata hex is 0xa9059cbb0000000000000000000000001111111111111111111111111111111111111111000000000000000000000000000000000000000000000000de0b6b3a7640000 — should I let it proceed or manually review this before signing?"},{"title":"Detect dangerous bytecode in token contract","prompt":"Before I interact with this contract, I need you to check if the bytecode looks suspicious and flag any dangerous selectors. Analyze this transaction: target is 0x9876543210987654321098765432109876543210, no value transfer, and calldata is 0x23b872dd000000000000000000000000feeddeadfeeddeadfeeddeadfeeddeadfeeddead000000000000000000000000cafecafecafecafecafecafecafecafecafecafe0000000000000000000000000000000000000000000000008ac7230489e80000 — give me a clear sign, avoid, or manual-review verdict."}],"resultDescription":"A verdict of sign, avoid, or manual-review along with a decoded breakdown of the transaction shape (target, value, data), identified selectors (e.g. ERC-20 approve or transfer), bytecode probe results, and specific risk flags that informed the decision.","failureModes":["Malformed or missing calldata returns a decoding error","Unverified or non-contract target address may limit bytecode analysis","Network issues reaching the EVM node cause probe failures","Invalid transaction structure returns a 400-level validation error","Payment not confirmed via x402 results in 402 response blocking the call"],"whenToPreferThis":"Use this endpoint when an AI agent needs to autonomously evaluate an EVM transaction before signing or submitting it on-chain — especially when detecting token approvals, unlimited allowances, or suspicious transfer selectors matters. Prefer this over generic contract explorers when you need a machine-readable sign/avoid/manual-review verdict packaged for agent consumption, and when paying per-call via x402 on Base is acceptable.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T18:30:51.247Z","isFirstParty":false}