Release Streak (token symbol STREAK) on Sepolia as a univ4_hook launch.

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

Hook: BuyStreakHook, a Uniswap v4 hook on the token's native-ETH pool that rewards daily buyers with a lower fee.

Days: day = block.timestamp / 86,400 (UTC). Streaks are per pool and per identity (rule below). A qualifying buy is zeroForOne with an ETH leg of at least 0.0005 ETH; on one, if lastDay == today nothing changes, if lastDay == today - 1 then streak += 1, otherwise streak = 1; then lastDay = today and StreakUpdated(poolId, user, day, streak) is emitted.

Effective streak = streak when lastDay >= today - 1, else 0 (a missed day resets). Every swap in both directions pays max(100 - 10 x effective streak, 30) bps of its ETH leg, priced from the streak before this swap updates it (1% at 0, 0.9% at 1, down to 0.3% from day 7), charged with the ETH-leg mechanics below. Sells never extend a streak.

Fees accrue as ETH claims whose only destination is permissionless burnFees(), which takes them all to 0x000000000000000000000000000000000000dEaD.

Views: streakOf(poolId, user) returning streak, lastDay, effective streak and fee bps now; feeFor(poolId, user). 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 updates no streak. 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 STREAK, fee 3000, tickSpacing 60) and seeds one-sided STREAK 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 write-foundry-tests step lists (UTC day boundary, two buys in a day, a missed day, the 0.3% floor, the 0.0005 ETH threshold, sells, burnFees, pool isolation, a mismatched hookData).

The independent adversarial review (read-only) attacks the hookData == tx.origin check, day arithmetic, any way to extend or borrow a streak without a qualifying buy, 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 streak, a 30-day calendar built from StreakUpdated events, and the fee it would pay right now. Streak is a Sepolia test toy: its token and any pot have no value, and nothing here promises a return.