TickHarberger

How it works

An automated market maker charges the same fee everywhere, which is the same as saying it believes every price level is equally valuable to trade at. No venue with a human on it believes that. The flow near the current price is worth something quite different from the flow forty percent away, and it changes hour by hour, and a governance vote on a single pool-wide number is not a mechanism for discovering it.

Auction-managed AMMs answered this by selling the right to set the fee for the whole pool, which is a real improvement and still one number. This sells it per tick range. Somebody who believes the band the price is sitting in is worth more than the market thinks can buy exactly that band, and nothing else.

The lease is Harberger. A holder names their own price for the range and pays continuous rent on that number, and anybody may take the range from them at any moment by paying it. Naming a low price is cheap and loses the range; naming a high one keeps it and costs.

There is no auction to run, no round to wait for, and nobody who decides who wins: the holder's own valuation is both the tax base and the strike, which is what makes the two honest at once. Rent accrues only while a range holds the current price, which is the only time the right is worth anything. That is not a concession, it is what makes squatting self-defeating: holding a distant range costs nothing, and the valuation that makes it free to hold is also the price at which it is taken away the moment it becomes valuable.

Rent goes to the pool's liquidity providers by donation, so the people whose capital is being priced are the people paid for it. What the leaseholder earns is the fee they set, taken on top of the pool's own, which is the position they paid rent to occupy.

Using it

Uniswap v4 removed hookData from initialize, so per-pool parameters arrive out of band. Fix them for a pool key whose pool does not exist yet, then initialize. Nobody can change them afterwards, including you.

hook.configure(
    key,
    TickHarbergerHook.Config({
        rangeWidth: /* int24 */ 0,
        rentRateBps: /* uint32 */ 0,
        maxFeePips: /* uint24 */ 0,
        minDeposit: /* uint128 */ 0
    })
);

poolManager.initialize(key, startingSqrtPriceX96);

Parameters

From TypeScript

npm i @hookforge/sdk

import {getHook, hookAddress, poolKeyFor} from "@hookforge/sdk";

const hook = getHook("tick-harberger");
const key  = poolKeyFor({
  hook: hookAddress("tick-harberger", 8453),   // Base
  currencyA: USDC, currencyB: WETH,
  tickSpacing: 60,
});

What it reverts with

The callbacks it claims

Uniswap v4 reads a hook's permissions from the low fourteen bits of its own address, which is why deploying one means mining a CREATE2 salt. This hook claims 4, so every deployment of it has an address ending in 0x10c4.

• beforeInitialize
• afterInitialize
• beforeAddLiquidity
• afterAddLiquidity
• beforeRemoveLiquidity
• afterRemoveLiquidity
• beforeSwap
• afterSwap
• beforeDonate
• afterDonate
• beforeSwapReturnsDelta
• afterSwapReturnsDelta
• afterAddLiquidityReturnsDelta
• afterRemoveLiquidityReturnsDelta

It says what it is, on-chain

Nothing about a hook's address tells an indexer, a wallet, a router or an agent what the pool does, which is why hook discovery today is a curated list. This hook answers for itself, in one eth_call, with no registry in the loop.

cast call $HOOK "hookName()(string)"    # TickHarberger
cast call $HOOK "specURI()(string)"     # https://tick-harberger.pages.dev/hook.json
cast call $HOOK "hookTags()(string[])"  # fees, harberger, auction, mev, no-admin

Build, test and deploy

git clone --recurse-submodules https://github.com/nirholas/tick-harberger
cd tick-harberger
forge build && forge test

# Dry run: mines the salt, prints the address, sends nothing.
forge script script/Deploy.s.sol --rpc-url $RPC_URL

# For real.
forge script script/Deploy.s.sol --rpc-url $RPC_URL --broadcast --verify

Try it

This is the hook running, not a picture of it. Connect a wallet on a chain it is deployed to, or bring the whole stack up locally in one command and use it with no funds and no wallet risk at all.

git clone --recurse-submodules https://github.com/nirholas/tick-harberger
cd tick-harberger

anvil &
forge script script/DeployLocal.s.sol --rpc-url http://127.0.0.1:8545 --broadcast \
  --private-key 0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80

node web/build.mjs && npx serve web/dist