ZkPadMevDescendingFees

Source: contracts/src/mev/ZkPadMevDescendingFees.sol · Interfaces: IZkPadMevModule, IZkPadMevDescendingFees · Port of Clanker v4 ClankerMevDescendingFees. GPL-2.0-or-later.

User-level explanation: anti-sniper descending fee.

Configuration

struct FeeConfig {
    uint24 startingFee;     // pips, > 0, >= endingFee, <= hook.MAX_MEV_FEE() (800_000)
    uint24 endingFee;       // pips, normally the pool's fee F
    uint256 secondsToDecay; // > 0, <= hook.MAX_MEV_MODULE_DELAY() (120)
}

Passed as MevModuleConfig.mevModuleData = abi.encode(FeeConfig).

Fee curve

timeDecay = secondsToDecay - (now - (poolStartTime + DELAY_GUARD))
fee       = endingFee + (startingFee - endingFee) * (timeDecay / secondsToDecay)^2

• DELAY_GUARD = 1 second: decay starts one second after deployment.
• beforeSwap reverts with SameSecondAsDeployment in the launch second.
• At now >= poolStartTime + secondsToDecay + DELAY_GUARD the module returns disableMevModule = true and emits DecayPeriodOver.
• The hook applies the module fee only if it exceeds the pool's normal fee.

Functions

Function	Access	Description
initialize(PoolKey, bytes poolFeeConfig)	the pool's hook	Store config and start time (once per pool)
beforeSwap(PoolKey, SwapParams, bool, bytes) returns (bool disableMevModule)	the pool's hook	Compute the fee and call hook.mevModuleSetFee
getFee(PoolId) view returns (uint24)		Current module fee (0 when not running)
feeConfig(PoolId) view, poolStartTime(PoolId) view		State
supportsInterface(bytes4) pure		ERC-165

Events and errors

Events: FeeConfigSet(poolId, startingFee, endingFee, secondsToDecay), DecayPeriodOver(poolId).

Errors: OnlyHook, PoolAlreadyInitialized, StartingFeeMustBeGreaterThanZero, StartingFeeMustBeGreaterThanEndingFee, TimeDecayMustBeGreaterThanZero, OnlyZkPadHook, SameSecondAsDeployment, TimeDecayLongerThanMaxMevDelay, StartingFeeGreaterThanMaxMevFee, PoolLocked.