MemespadHook

A trading tax hook. It takes a tax on trades, manages its own liquidity and trades on its own.

• Takes a tax on trades

  On top of the normal pool fee, it keeps part of each trade as a tax. Buys and sells can be taxed differently.

  The code that does this (beforeSwap):

  function beforeSwap(
      address sender,
      PoolKey calldata key,
      SwapParams calldata params,
      bytes calldata
  ) external onlyPoolManager returns (bytes4, BeforeSwapDelta, uint24) {
      if (sender == address(this) || sender == address(factory))
          return (this.beforeSwap.selector, toBeforeSwapDelta(0, 0), 0);
  
      (address tokenAddr, bool tokenIsZero_) = _identifyToken(key);
      if (tokenAddr == address(0)) return (this.beforeSwap.selector, toBeforeSwapDelta(0, 0), 0);
  
      bool isBuy_ = tokenIsZero_ ? !params.zeroForOne : params.zeroForOne;
  
      if (isBuy_ && sender != address(factory) && block.timestamp < snipeWindowEnd[tokenAddr]) {
          revert SnipeWindowActive();
      }
  
      if (isBuy_ && params.amountSpecified < 0 && sender != address(factory)) {
          uint256 mbc = maxBuyQuoteByToken[_poolQuote(key, tokenIsZero_)];
          if (mbc > 0 && block.timestamp < fairLaunchEnd[tokenAddr]) {
              if (SafeCast.toUint256(-params.amountSpecified) > mbc) revert MaxBuyExceeded();
          }
      }
  
      TaxParams storage p = taxParams[tokenAddr];
      uint256 totalTaxBps = isBuy_ ? uint256(p.buyTaxBps) : uint256(p.sellTaxBps);
      if (totalTaxBps == 0) return (this.beforeSwap.selector, toBeforeSwapDelta(0, 0), 0);
  
      bool ethIsSpecified = params.zeroForOne == (params.amountSpecified < 0);
      // …

• Manages its own liquidity

  It adds and removes liquidity itself, so it can own part or all of the pool.

  The code that does this (tryAddLiquidity):

  function _tryAddLiquidity(
      PoolKey calldata key,
      address tokenAddr,
      bool tokenIsZero_
  ) internal {
      address quoteToken_ = _poolQuote(key, tokenIsZero_);
      if (quoteToken_ != taxParams[tokenAddr].quoteToken) return; // auto-liquidity: main pool only
      uint256 pending     = pendingLiq[tokenAddr][quoteToken_];
      uint256 threshold   = liquidityThreshold[tokenAddr];
      if (threshold == 0 || pending < threshold) return;
  
      pendingLiq[tokenAddr][quoteToken_] = 0;
  
      // Step 1: swap ~45% of accumulated quote for tokens (slightly under half to
      // avoid ratio mismatch when providing two-sided liquidity)
      uint256 swapAmt = (pending * 45) / 100;
      uint256 keepAmt = pending - swapAmt;
      bool zeroForOne = !tokenIsZero_;  // sell quote to buy tokens
  
      BalanceDelta swapDelta = IPoolManager(poolManager).swap(
          key,
          SwapParams({
              zeroForOne:        zeroForOne,
              amountSpecified:   -int256(swapAmt),
              sqrtPriceLimitX96: zeroForOne ? MIN_SQRT_PRICE_LIMIT : MAX_SQRT_PRICE_LIMIT
          }),
          ""
      );
  
      // Settle the quote we sold
      // …

• Trades on its own

  It makes trades itself, for example to convert the fees it collected.

  The code that does this (tryExecuteBurn):

  function _tryExecuteBurn(
      PoolKey calldata key,
      address tokenAddr,
      bool tokenIsZero_
  ) internal {
      address quoteToken_ = _poolQuote(key, tokenIsZero_);
      uint256 pending     = pendingBurn[tokenAddr][quoteToken_];
      if (pending == 0) return;
      uint256 threshold   = quoteToken_ == taxParams[tokenAddr].quoteToken
          ? burnThreshold[tokenAddr] : extraBurnThreshold[tokenAddr][quoteToken_];
      if (threshold == 0) threshold = burnDustThresholdByToken[quoteToken_];
      if (threshold > 0 && pending < threshold) return;
  
      pendingBurn[tokenAddr][quoteToken_] = 0;
  
      bool zeroForOne = !tokenIsZero_;
  
      BalanceDelta delta = IPoolManager(poolManager).swap(
          key,
          SwapParams({
              zeroForOne:        zeroForOne,
              amountSpecified:   -int256(pending),
              sqrtPriceLimitX96: zeroForOne ? MIN_SQRT_PRICE_LIMIT : MAX_SQRT_PRICE_LIMIT
          }),
          ""
      );
  
      if (quoteToken_ == address(0)) {
          uint256 ethOwed = tokenIsZero_
              ? SafeCast.toUint256(-int256(delta.amount1()))
      // …

• Launch protection

  It limits trading, for example a max buy or wallet size or a cooldown, to stop bots grabbing the supply before real traders.

  The code that does this (beforeSwap):

  function beforeSwap(
      address sender,
      PoolKey calldata key,
      SwapParams calldata params,
      bytes calldata
  ) external onlyPoolManager returns (bytes4, BeforeSwapDelta, uint24) {
      if (sender == address(this) || sender == address(factory))
          return (this.beforeSwap.selector, toBeforeSwapDelta(0, 0), 0);
  
      (address tokenAddr, bool tokenIsZero_) = _identifyToken(key);
      if (tokenAddr == address(0)) return (this.beforeSwap.selector, toBeforeSwapDelta(0, 0), 0);
  
      bool isBuy_ = tokenIsZero_ ? !params.zeroForOne : params.zeroForOne;
  
      if (isBuy_ && sender != address(factory) && block.timestamp < snipeWindowEnd[tokenAddr]) {
          revert SnipeWindowActive();
      }
  
      if (isBuy_ && params.amountSpecified < 0 && sender != address(factory)) {
          uint256 mbc = maxBuyQuoteByToken[_poolQuote(key, tokenIsZero_)];
          if (mbc > 0 && block.timestamp < fairLaunchEnd[tokenAddr]) {
              if (SafeCast.toUint256(-params.amountSpecified) > mbc) revert MaxBuyExceeded();
          }
      }
  
      TaxParams storage p = taxParams[tokenAddr];
      uint256 totalTaxBps = isBuy_ ? uint256(p.buyTaxBps) : uint256(p.sellTaxBps);
      if (totalTaxBps == 0) return (this.beforeSwap.selector, toBeforeSwapDelta(0, 0), 0);
  
      bool ethIsSpecified = params.zeroForOne == (params.amountSpecified < 0);
      // …

Who controls it: The code itself can’t be changed. The hook developer can change: treasury, fair launch window, max buy quote, token tax, factory, dividend pool and 6 more. The hook developer can also call: emergency withdraw.

Based on the hook’s published code.