Pre-Sign Function Call Decoder

WHAT IT DOES

Pre-Sign Function Call Decoder takes any Ethereum transaction or raw call data and shows you exactly what function is being called, what parameters are passed, and what it all means in plain English. It resolves the 4-byte method ID to a human-readable function name, decodes each parameter from hex to readable values (addresses, numbers, booleans), and flags suspicious patterns like unlimited approvals, ownership changes, self-destruct, and large transfers. An AI layer then translates the entire function call into a clear explanation of what the transaction does, what permissions it requests, and what assets are affected—all before your wallet ever asks for a signature.

HOW TO USE

Connect your EVM wallet using the BotGentz wallet bridge. Select the network matching your transaction. Paste a transaction hash to fetch and decode the full transaction from the chain, or paste raw hex call data (starting with 0x) to decode it directly. Click "Decode"—the tool resolves the method ID, extracts all parameters, flags risks, and generates an AI explanation. Results show you the method ID, function name, signature, each parameter with its decoded value, risk flags, and a plain-English explanation of what the function call does. No transaction is ever submitted—this tool is read-only and free.

TECHNICAL MECHANISM

The app uses the injected BGWallet bridge to access the EVM provider via ethers.js v5.7.2. Transaction hashes are fetched via provider.getTransaction(). Call data (the hex string starting after the method ID) is decoded against a built-in 4-byte signature database covering common ERC20 functions (transfer, approve, transferFrom, allowance, balanceOf), ERC721 functions (ownerOf, safeTransferFrom, transferFrom, setApprovalForAll), mint functions, admin functions (owner, renounceOwnership, transferOwnership, pause, unpause), withdraw, and selfdestruct. Parameter decoding extracts each field by position from the hex data—addresses are padded to 64 hex characters (20 bytes), uint256 values are converted from hex to decimal using ethers.BigNumber, and booleans are checked against the canonical hex values. The decoded function name, parameters, method ID, and any detected flags are passed to the AI bridge (BGAI.generate), which returns a plain-English explanation capped at 1,024 tokens.

WHAT IT CANNOT SEE

This tool cannot detect malicious intent hidden in contract bytecode—it reads only the function call data visible on-chain. It cannot verify that the resolved function name from the 4-byte database matches the actual contract implementation—any contract can implement a function with the same method ID but completely different behavior. It cannot verify off-chain consequences of a transaction. It cannot detect cross-contract exploits, reentrancy vulnerabilities, or front-running attempts. It does not simulate transaction execution, so it cannot predict revert conditions or gas exhaustion. The AI explanation is generated from the provided data and may miss nuanced attack patterns not present in the call data itself.

PLEASE NOTE

Supports EVM-compatible chains only—Ethereum, Sepolia, Polygon, Mumbai, Optimism, Arbitrum, and any network the wallet bridge connects to. The 4-byte signature database is built-in and covers the most common functions—if a function is not in the database, the tool will show the method ID and raw data but cannot provide a function name. Explanations are AI-generated and should be treated as assists, not authoritative audits. Always review the transaction details in your wallet's own signature prompt before approving. The wallet's signature step is the only protection that actually gates any action—this tool is informational and does not replace that safeguard. Free to use, no API keys required.