Pre-Sign Unlimited-Spend Warning Tool

WHAT IT DOES

Pre-Sign Unlimited-Spend Warning Tool reads pending approval transaction data from your wallet or a transaction hash, decodes the function (approve, setApprovalForAll, or permit), and extracts the spender address and approval amount or scope. It detects whether the approval is unlimited (setApprovalForAll with true, or approve with the max uint256 value) or effectively unlimited (an amount far exceeding your current balance). The tool provides a clear warning if unlimited spend is detected, explaining what the spender could do with the permission.

HOW TO USE

When your wallet prompts you to sign an approval transaction, copy the transaction hash from your wallet or the requesting dApp. Open the Pre-Sign Unlimited-Spend Warning Tool, connect your EVM wallet, and paste the transaction hash into the input field. Click "Look up transaction" to fetch the approval details and generate an analysis. Alternatively, click "Manual entry" to enter the token contract address, spender address, amount, and function type directly. The tool will display the contract address, spender, function, amount, and a clear warning if the approval is unlimited. Review the AI explanation to understand the risks, then verify the details in your wallet before signing.

TECHNICAL SECTION — UNLIMITED SPEND DETECTION

The tool fetches transaction data from the blockchain using the connected wallet's provider. It decodes the function signature and arguments for approve, setApprovalForAll, and permit calls. For approve and permit, it extracts the spender address and the approval amount. For setApprovalForAll, it extracts the operator address and the boolean approval value. The tool then detects unlimited spend by checking: setApprovalForAll with true (unlimited permission for all tokens in the collection), approve with the max uint256 value (115792089237316195423570985008687907853269984665640564039457584007913129639935), or an amount that is more than 10 times the user's current balance (effectively unlimited). When unlimited spend is detected, the tool generates a prominent warning. The AI layer receives the decoded data and provides a plain-language explanation of the risk. This approach helps you identify potentially dangerous approvals before you sign.

WHAT IT CANNOT SEE

This tool cannot read the actual intent behind an approval transaction. It cannot determine if the spender address is malicious without an external database. It cannot detect if the approval amount is truly unlimited versus a large but finite number without comparing to the wallet balance. It cannot predict if the spender will use the approval. It cannot detect if the approval has been revoked at the time of the check. The user must still verify the transaction details in their wallet before signing. The AI explanation is generated from on-chain data and does not constitute financial advice or a security guarantee.

PLEASE NOTE

EVM chains only. Explanations are AI-generated from data the app reads on-chain—always review what you are actually signing in your wallet before approving it. The wallet's own signature prompt remains the final and only protection against unwanted approvals. This tool is read-only; it never sends transactions or signs anything on your behalf.