Hook Tax

A hook tax is the part of a swap that a Uniswap V4 pool's hook keeps, beyond the pool's fee and apart from the token's own tax.

A Uniswap V4 pool can attach a hook, a contract that runs on every swap. The hook can take a cut of the trade or set its own dynamic fee, so the trader gets less than the pool's price and fee would give, even when the token itself charges no tax. Tok{In} measures it per pool: it compares what the simulated swap paid out with what the pool alone pays for the same trade. A trade pays both cuts, one after the other, so it loses a little less than their sum. Check both.