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EVM Transaction Preflight for Agents
x402
EVM Transaction Preflight for Agents is a paid API for AI agents from x402-market-intel-mcp.mtree.workers.dev, paid per call via x402, $0.15/call, status unknown (last checked 2026-09-13).
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.
Price / call$0.15
Success—
StatusUnknown
How this service works
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.
Output
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.
Example use cases
Review token approval before signing
“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?”
Preflight check suspicious contract interaction
“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?”
Detect dangerous bytecode in token contract
“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.”
Technical details
Endpoint
POSThttps://x402-market-intel-mcp.mtree.workers.dev/v1/x402/tx_preflight_for_agentsWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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