Pre-Sign Side-Effect Explainer

WHAT IT DOES

Pre-Sign Side-Effect Explainer simulates your transaction and shows you exactly what would change if you sign. It decodes the function, runs a dry-run simulation, and detects all side-effects: token transfers, approvals granted or revoked, ownership changes, withdrawals, self-destruct calls, and ETH movements. It tells you whether the transaction would succeed or fail, and what the real-world impact would be on your wallet and assets. An AI layer translates everything into plain English—so you know exactly what signing would do, not just what the transaction data says.

HOW TO USE

Connect your EVM wallet using the BotGentz wallet bridge. Select your network. Paste a transaction hash to fetch and analyze, or paste raw call data (hex) to decode directly. Click "Explain"—the tool decodes the function, simulates the transaction, detects side-effects, and generates an AI explanation. Results show you the simulation status (succeed/fail), sender, recipient (with EOA/contract badge), value, function name, parameters, a list of detected side-effects, risk flags, and a plain-English explanation of what signing would actually do. 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 is decoded against a built-in 4-byte signature database covering common functions (transfer, approve, transferFrom, safeTransferFrom, setApprovalForAll, ownerOf, mint, owner, transferOwnership, renounceOwnership, withdraw, selfdestruct, pause, unpause). Parameter decoding extracts addresses, uint256 values, and booleans from the hex data. A dry-run simulation is performed using provider.call() with the transaction data—if the call fails, the revert reason is captured. Side-effect detection is based on the decoded function and parameters: token transfers, approvals, ownership changes, withdrawals, and self-destruct are flagged. Recipient bytecode is read via provider.getCode() to determine if the recipient is an EOA (no code) or a contract. The AI bridge (BGAI.generate) receives a prompt with the decoded data, simulation result, side-effects, and flags, and returns a plain-English explanation capped at 1,024 tokens.

WHAT IT CANNOT SEE

This tool cannot guarantee that simulation results match actual execution—state can change between simulation and submission. It 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 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 intent or consequences. It cannot detect cross-contract exploits, reentrancy vulnerabilities, or front-running attempts. It cannot detect state changes that occur through delegatecall or proxy patterns. The AI explanation is generated from the provided data and may miss nuanced attack patterns.

PLEASE NOTE

Supports EVM-compatible chains only—Ethereum, Sepolia, Polygon, Mumbai, Optimism, Arbitrum, and any network the wallet bridge connects to. The 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. Simulations are estimates based on current state. Explanations are AI-generated and should be treated as assists, not authoritative guarantees. 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.