Spender Allowance Auto-Capper

WHAT IT DOES

The Spender Allowance Auto-Capper monitors any dApp page for token approval requests, detects the token contract and spender address being approved, and automatically caps the allowance to a user‑defined maximum amount—instead of the typical unlimited approval that most dApps request. When an approval is detected, the tool either intercepts the approval flow and submits a capped approval transaction (with your explicit signature) or, if auto‑cap is enabled, applies the cap immediately without requiring additional clicks. You can set a default cap amount (e.g., 100 tokens) and optionally whitelist trusted spender addresses to bypass the capping. This dramatically reduces your exposure to smart contract risk: even if a spender is compromised, they can only spend up to the capped amount rather than your entire token balance.

WHERE IT RUNS

It runs as a draggable overlay panel inside the BotGentz extension on any dApp that requests token approvals—Uniswap, SushiSwap, 1inch, Curve, Aave, Compound, OpenSea, Rarible, and thousands of other DeFi and NFT platforms. It works by scanning the page's DOM for approval‑related elements and extracting addresses and context.

HOW TO USE

1. Install the free BotGentz extension and ensure you have an EVM‑compatible wallet extension installed (e.g., MetaMask, Rabby, Trust Wallet).

2. Navigate to any dApp where you might approve a token.

3. Click the BotGentz icon and select "Spender Allowance Auto-Capper" from the tools menu.

4. Click "Start Watching" to begin monitoring the page.

5. When an approval request is detected, a suggestion card appears showing the token, spender, and a cap input field.

6. Enter or confirm the cap amount and click "Apply Cap"—or enable "Auto-apply cap" in settings to apply automatically.

7. The tool submits a capped approval transaction for you to sign in your wallet.

8. Once confirmed, the allowance is capped to your specified amount.

9. Drag the panel to reposition it, resize it, collapse it, or press Escape to close.

THE ACTUAL MECHANISM — DOM‑driven approval detection with dynamic transaction substitution

This tool uses a proactive monitoring engine that combines DOM mutation observation with on‑chain verification. First, a MutationObserver watches the page for changes and scans for elements likely to trigger approvals—buttons with text like "Approve", "Enable", "Unlock", or "Allow". Second, when such an element is detected, the tool extracts nearby Ethereum addresses using regex matching on visible text and attributes, identifying the token contract (usually the first address) and the spender (the second address). Third, it fetches the token's decimals and the current allowance via `eth_call` to determine whether an approval already exists and whether it is unlimited. Fourth—and most critically—when the user confirms the cap, the tool builds an `approve(address spender, uint256 amount)` transaction using the ethers.js library (loaded at runtime), encodes the cap amount with the correct decimals, and submits it via `window.ethereum.request({ method: "eth_sendTransaction" })`. This effectively replaces the unlimited approval the dApp intended with a capped one, using the same standard interface. The user signs the transaction in their wallet, and the allowance is set to the finite amount—all without requiring any changes to the dApp's code.

THE PANEL

The panel is fully draggable by its title bar and snaps to the nearest edge of the viewport when released. You can resize it horizontally by dragging the left or right border; the height expands to fit content up to a maximum, with scrolling inside the suggestions list. A collapse button minimizes the panel to a small floating chip showing "⚙️ Auto-Capper" — click it to expand back. Press Escape at any time to close the panel entirely. The panel remembers its last position, size, and expansion state per domain via localStorage.

PLEASE NOTE

- This tool requires the free BotGentz extension and a real EVM wallet extension (e.g., MetaMask) already installed in your browser. It does not include a wallet—it connects to the one you already have.

- This tool works only on EVM‑compatible chains (Ethereum, BSC, Polygon, Arbitrum, Optimism, and others supported by your wallet).

- The tool cannot intercept or modify transactions that are submitted directly through a wallet interface without page interaction. It cannot cap approvals for tokens that use non‑standard approve functions (e.g., USDT's approve with different semantics). It cannot enforce a cap if the user manually edits the transaction parameters in their wallet to a higher amount. It cannot detect approvals that are initiated via contract calls that do not use the standard approve function signature.

- No private keys, seed phrases, or sensitive data are ever read, stored, or transmitted. All transactions are signed and sent directly from your wallet. Approval data and settings are stored locally in your browser's extension storage. Only anonymized usage metrics (panel open/close, approval detections) are collected; you can disable this in the extension settings at any time.