Approval Amount Sanity Checker

WHAT IT DOES

The Approval Amount Sanity Checker reads the parameters of a pending ERC‑20 approve() transaction—token address, spender address, allowance amount, and optional decimals—and checks whether the approval amount is reasonable relative to your actual token balance. It fetches your balance via balanceOf() on the token contract, checks if the spender is a contract or EOA via eth_getCode, and determines if the approval amount exceeds your balance by an unusual margin, is unlimited, or is otherwise suspicious. It then uses AI to provide a plain‑language assessment before you sign.

HOW TO USE

1. Connect your EVM wallet (required to read your token balance).

2. Select the chain (Ethereum, Polygon, or Arbitrum).

3. Enter the token contract address, spender address, allowance amount, and optional token decimals.

4. Click "Check sanity" to fetch your balance and run the checks.

5. Review the sanity check result (PASS/FAIL), the raw data, and the AI explanation.

6. The wallet's own signature prompt will still appear—this tool only informs you.

THE REAL MECHANISM — balance‑based sanity checking with AI explanation

This tool reads the user‑provided approval parameters and performs a series of checks. It calls balanceOf() on the token contract via eth_call to get your current token balance. It checks eth_getCode on the spender address to determine if it's a contract or an EOA. It then compares the approval amount to your balance: if the approval amount is unlimited, it's flagged as high risk. If the approval amount exceeds your balance by more than 20%, it's flagged as suspicious (50%+ for high risk). The tool passes the decoded parameters and the balance comparison to the AI bridge (BGAI.generate), which produces a concise explanation of the sanity check result. The AI is instructed to flag unlimited approvals and large‑ratio approvals.

WHAT IT CANNOT SEE

- This tool cannot read the exact intent behind the approval—only the on‑chain parameters.

- It cannot determine if the spender contract is malicious with certainty, only whether it is verified or has known patterns.

- It cannot detect approvals that are submitted through a wallet interface without page interaction.

- It cannot read off‑chain agreements or promises related to the approval.

- It cannot verify if the token contract's decimals are non‑standard without additional calls.

- It cannot prevent you from signing a transaction—it only provides information.

PLEASE NOTE

- This tool works on Ethereum (1), Polygon (137), and Arbitrum (42161).

- You must enter the approval parameters manually—this tool does not intercept wallet transactions.

- The AI explanation is generated from the data you provide and is for guidance only. Always review the actual transaction details in your wallet before signing.

- The wallet's own signature prompt is what actually protects you—the AI's read is not a substitute for reviewing what you sign.