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AgentTools EVM Transaction Explainer
x402
AgentTools EVM Transaction Explainer is a paid API for AI agents from agenttools-hub.vercel.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).
Decodes EVM transaction calldata and simulates the call against live chain state to report what it would do — including token transfer details, approval amounts, and unlimited-approval warnings — without broadcasting anything.
Price / call$0.005
Success—
StatusUnknown
How this service works
Explain what an EVM transaction would actually do: decodes the calldata (ERC-20 transfers/approvals via known ABIs, unknown selectors via the 4byte directory) and simulates the call against live chain state to report the outcome — including unlimited-approval warnings — without sending anything. Use this when an agent needs to decode and simulate a transaction — before signing it.
Output
Returns a structured explanation of the transaction including the decoded function name and arguments (e.g. ERC-20 transfer recipient and amount, or approval spender and value), the simulated outcome against live on-chain state, and any security warnings such as unlimited token approvals — all without submitting the transaction to the network.
Example use cases
Catch unlimited token approval
“Before I confirm this transaction, decode and simulate what this calldata does on Ethereum — to is 0xdAC17F958D2ee523a2206206994597C13D831ec7 and data is 0x095ea7b3000000000000000000000000someprotocol00000000000000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff — is this trying to get unlimited USDT approval?”
Preview ERC-20 transfer details
“Can you decode and simulate this transaction on Base before I sign it? The to address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 and calldata is 0xa9059cbb000000000000000000000000recipientaddress0000000000000000000000000000000000000000000000000000000000002710 — I want to see exactly how many tokens would be transferred and to whom.”
Identify unknown contract call
“I have a transaction with an unknown function selector I don't recognize — to is 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45 and data is 0x5ae401dc00000000000000000000000000000000000000000000000000000000649f2b40 on Ethereum. Can you decode the calldata and simulate what it would actually do before I approve it?”
Technical details
Endpoint
GEThttps://agenttools-hub.vercel.app/api/v1/crypto/tx-explain?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent or user needs to understand what a raw EVM transaction would do before signing — especially for security-critical scenarios like detecting unlimited token approvals or decoding unfamiliar calldata. Prefer this over generic ABI decoders because it combines calldata decoding with live chain simulation and security warnings in one call, and supports both Base and Ethereum.
Side effects
- Unknown calldata selector not found in 4byte directory returns partial decode
- Simulation fails if to address is not a deployed contract on the specified chain
- Invalid hex calldata returns a parsing error
- Chain not specified defaults to a single chain and may miss cross-chain context
- RPC node unavailability can cause simulation failure
- Value parameter mismatch may cause simulation to revert differently than real execution
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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