Release Tiers (token symbol TIER) on Sepolia as a univ4_hook launch.

Token: Tiers (TIER), total supply 1,000,000,000 TIER with 18 decimals, minted once to the deployer.

Hook: LoyaltyTierHook, a Uniswap v4 hook on the token's native-ETH pool that discounts its fee by lifetime volume.

Volume: lifetime ETH leg per pool and identity (rule below), uint128, added after the swap's fee is priced. Every swap in both directions pays, priced from the volume before this swap: 100 bps below 0.01 ETH, 75 bps from 0.01 ETH, 50 bps from 0.1 ETH, 25 bps from 1 ETH (thresholds inclusive), charged with the ETH-leg mechanics below. Fees accrue as ETH claims whose only destination is permissionless burnFees(), which takes them all to 0x000000000000000000000000000000000000dEaD.

Events: VolumeAdded(poolId, user, ethLeg, total, tier).

Views: volumeOf, tierOf, feeBpsOf, nextTierAt(poolId, user). Economics for the README: reaching a tier costs the fees paid on the way, so tiers cannot be farmed for free, and volume in one pool never discounts another. ETH-leg fee mechanics (as live launch 170's MedallionHook): a buy is zeroForOne (ETH in), a sell oneForZero (ETH out), and the swapper's specified amount is always honoured exactly.

With ETH specified (exact-in buys, exact-out sells) the fee is a positive specified BeforeSwapDelta in beforeSwap of floor(|amountSpecified| x bps / 10,000); with ETH unspecified (exact-out buys, exact-in sells) it is a positive unspecified delta in afterSwap of floor(ETH the pool moved x bps / 10,000). That fee base is the swap's ETH leg. A partial fill (price limit hit) reverts with PartialFill.

The hook settles each fee by minting itself ERC-6909 ETH claims (poolManager.mint) inside the swap, never take() or an ETH transfer in a callback, so the first buy into the ETH-less pool works; every payout burns claims and takes ETH in the hook's own unlockCallback, balance zeroed first (CEI). A fee that rounds to 0 is 0, so dust never reverts.

Invariant: the hook's ETH claims at the PoolManager equal everything it still owes.

Identity: abi.decode(hookData, (address)) only when hookData is exactly 32 bytes, non-zero and equal to tx.origin, so nobody can borrow another address's standing to lower a fee; any other swap has no identity, pays the full 1% and adds no volume. tx.origin only confirms that claim for pricing and never authorises moving funds; the README says smart-contract wallets (signed by a bundler or relayer) never earn a discount.

Deploy shape (as live Sepolia hook launches 170, 183 and 186, constructor per the context): every rate, window and threshold is a source constant; no admin, setter, pause, upgrade or sweep. Permissions are exactly beforeSwap, afterSwap, beforeSwapReturnDelta and afterSwapReturnDelta (address bits 0x00CC), all others false, checked by Hooks.validateHookPermissions in the constructor with a CREATE2 salt mined for those bits.

The factory initializes the pool (currency0 native ETH, currency1 TIER, fee 3000, tickSpacing 60) and seeds one-sided TIER liquidity; the hook must revert neither, and the first buy lands in a pool with no ETH. State is keyed by PoolId; a pool whose currency0 is not native ETH gets zero deltas and no other effect. Every callback requires msg.sender == PoolManager.

Tests (Foundry, a real v4-core PoolManager deployed in the test, hook at a mined address): a launch rehearsal that initializes at the manifest price, seeds one-sided liquidity like the factory and makes the first buy into the ETH-less pool; all four swap modes; dust; a non-ETH pool; non-PoolManager callers revert; fuzzed sizes; and the cases the build step lists (each threshold at and 1 wei below, a threshold-crossing swap paying the old rate, pool isolation, mismatched or missing hookData, burnFees).

The independent adversarial review (read-only) attacks the hookData == tx.origin check, threshold arithmetic, volume overflow, farming tiers through a private pool, fee sign and rounding on all four swap modes, and burnFees accounting; its step lists each target.

Website: one static page (dist/index.html) reading the hook's views and events, with a buy/sell form that swaps through the Sepolia PoolSwapTest router named in the site step and puts the connected wallet in hookData; it shows the connected wallet's tier, volume to the next tier, the tier table and the fee its next swap would pay. Tiers is a Sepolia test toy: its token and any pot have no value, and nothing here promises a return.