MuseLinuHook

A fee on trades hook. It takes a cut of every trade.

• Takes a cut of every trade

  On top of the normal pool fee, it can keep a share of each trade for itself.

  The code that does this (beforeSwap):

  function beforeSwap(
      address,
      PoolKey calldata key,
      IPoolManager.SwapParams calldata params,
      bytes calldata
  ) external override returns (bytes4, BeforeSwapDelta, uint24) {
      if (PoolId.unwrap(key.toId()) != poolId) revert WrongPool();
      if (params.amountSpecified >= 0) {
          return (IHooks.beforeSwap.selector, BeforeSwapDeltaLibrary.ZERO_DELTA, 0);
      }
  
      // Input currency: zeroForOne ? currency0 : currency1.
      Currency inputCurrency = params.zeroForOne ? key.currency0 : key.currency1;
      uint256 inputAmount = uint256(-params.amountSpecified);
  
      if (Currency.unwrap(inputCurrency) == quote) {
          // Buy: 2% of the quote input to the collector.
          uint256 fee = (inputAmount * FEE_BPS) / 10000;
          if (fee == 0) return (IHooks.beforeSwap.selector, BeforeSwapDeltaLibrary.ZERO_DELTA, 0);
          poolManager.take(Currency.wrap(quote), collector, fee);
          emit FeeTaken(collector, Currency.wrap(quote), fee);
          return (IHooks.beforeSwap.selector, toBeforeSwapDelta(int128(int256(fee)), 0), 0);
      } else {
          // Sell: 1% of the MUSN input burned, capped at the floor.
          uint256 burn = _cappedBurn((inputAmount * BURN_BPS) / 10000);
          if (burn == 0) return (IHooks.beforeSwap.selector, BeforeSwapDeltaLibrary.ZERO_DELTA, 0);
          poolManager.take(Currency.wrap(token), DEAD, burn);
          emit Burned(DEAD, burn, _circulatingAfter());
          return (IHooks.beforeSwap.selector, toBeforeSwapDelta(int128(int256(burn)), 0), 0);
      }
      // …

Who controls it: No admin functions: nobody can change its rules after deployment.

Based on the hook’s published code.