Every other v4 hook redistributes a fee. This one replaces the curve.
The pool holds no liquidity. Every swap is intercepted in beforeSwap and
quoted by the hook out of its own reserves, so the hook is the counterparty on both
sides and keeps the entire spread — instead of leaking it to LPs and arbitrageurs.
The current Ethereum v4 hook cohort is remarkably uniform. Every project below intercepts a
swap, skims a fee, and routes it somewhere clever — holders, burns, tokenised equities,
NFT holders. Nobody touches beforeSwapReturnDelta, the one primitive that lets
a hook stop taxing the constant-product curve and replace it outright.
| Project | What the hook does | Where the value goes | Curve |
|---|---|---|---|
| Titanum · $Ti | Marks the pool rebase-excluded so reserves stay fixed | 3/3 tax → buyback & burn | Taxed |
| Loom · $LOOM | Token is the hook; tracks hold time per wallet | 3% ETH tax → holders × hold-time multiplier | Taxed |
| Stack · $STACK | Routes swap fees into a basket of tokenised equities | Fees → claimable stock dividends | Taxed |
| Crypt · $CRYPT | Asymmetric burn on ingress and egress | 1% in / 5% out → supply decay | Taxed |
| BRAH | 1% hook fee feeding an irreversible deposit wall | Daily print + swap fees → depositors | Taxed |
| Prism | One pool, NFT facets share the LP position | LP rewards → facet holders | Untouched |
| Nota · Unistreets | Launchpads pairing tokens against tokenised equities | Fees → creators or holders | Untouched |
| Programmable | Reviewed custom-hook launches with an onchain stamp | Infrastructure, not a mechanism | Untouched |
| ANVIL | Quotes every swap from its own reserves | Spread → a floor that can only rise | Replaced |
The marginal price is p₀ + slope · s / T. Trades are priced by integrating
that line across the trade, not by quoting one price for the whole size — so nobody
sweeps the book at the pre-trade ask.
This is where upside comes from. It is arithmetic, not a promise.
F = reserveETH ÷ circulating. Not a treasury policy, not a buyback budget —
the arithmetic mean of every wei that entered the contract. Redeemable by anyone, any
time, minus the exit fee.
Sell pressure does not drain it. Sell pressure raises it.
_assertFloorNonDecreasing re-derives the floor after every single swap and
reverts the transaction if it fell. There is no path through the contract that lowers it.
Five stateful invariants, 4096 randomised calls each, zero breaks.
Buyers walk up the bonding curve. The marginal price climbs toward 20× as the float is placed. Nothing exotic yet.
Every wei paid in stays in. The floor is what it buys back at. Early it is thin — it is still being built by the people buying.
The float is placed; trading is two-sided. Buys pay the spread, sells pay the exit fee, both stay in. The floor rises on volume alone.
The floor plus the minimum spread clears the curve. The floor is the ask now — fully backed, and only ratcheting.
| Parameter | Default | Hard cap | Effect |
|---|---|---|---|
| curveMultiplier | 20× | 1000× | Marginal price at full sellout, relative to p₀ |
| baseSpreadBps | 3.00% | 10.00% | Minimum spread once the floor is the binding ask |
| blockPremiumBps | 1.00% | 20.00% | Surcharge on the first swap of a block — the arbitrageur's swap |
| velocityCoefBps | 20.00% | 20.00% | Intra-block pressure: coef × blockVolume ÷ reserve |
| exitFeeBps | 1.00% | 5.00% | Retained on sells — this is what ratchets the floor |
| protocolFeeBps | 10.00% | 50.00% | Share of the collected fee, never of the trade |
| genesisBurnBps | 0.01% | 10.00% | Burned at seed so circulating supply is never zero |
BEFORE_INITIALIZE
BEFORE_ADD_LIQUIDITY
BEFORE_SWAP
BEFORE_SWAP_RETURNS_DELTA
CREATE2-mined so the low 14 bits carry exactly these permissions and nothing else.
Reserves and inventory sit as claim tokens inside the PoolManager. Swaps settle as pure
accounting — mint and burn. This is required, not an
optimisation: the swapper only settles after beforeSwap returns,
so a hook that tries to take real ETH mid-callback reverts.
Redirect the protocol-fee stream, and renounce. That is the entire surface. Pricing is immutable from construction.
Reserves are not withdrawable by anyone — only redeemable through the floor.
No. Custom-curve hooks that return a BeforeSwapDelta are the least
battle-tested part of Uniswap v4, and this contract holds the entire ETH reserve. The
suite covers unit, fuzz and stateful-invariant paths and every invariant holds over
thousands of randomised calls — but a test suite is not an audit. Do not put money into
an unaudited version of this.
Not through trading. Buys execute above F, sells retain the exit fee, and
the contract re-derives F after every swap and reverts if it fell. What the
floor cannot protect against is paying far above it — it is a redemption price, not a
purchase price.
You buy at the ask and can only ever redeem at the floor. Early, that gap is wide, because the floor is still being built. The terminal above prints exactly what you would lose exiting immediately, and how much two-sided volume it takes for the floor to reach your entry. The mechanism removes the "liquidity vanished" failure mode. It does not remove price risk.
Open question, and the single biggest practical launch risk. The pool reports no conventional liquidity because all quoting happens inside the hook. Some indexers may render liquidity as zero or misprice market cap. This gets verified on a testnet deployment before anything touches mainnet.
Because there is nothing to provide it to. The hook is the entire book. Adding liquidity
would recreate exactly the passive inventory arbitrageurs exist to extract from, which is
the problem this design removes. beforeAddLiquidity reverts unconditionally.
They all get paid, in order, at a floor that rises as they leave — the last seller gets a better price per token than the first. When the float is fully redeemed, only the permanently burned genesis slice remains circulating, and the residual reserve backs it.