Implemented swap counting in src/Hook.sol:

• Enabled beforeSwap.
• Added public per-PoolId swapCount getter.
• Increments once per swap in either direction.
• Returns zero delta and zero fee override.
• All other callback permissions remain disabled.

Verification:

• forge build: passed.
• forge test: 9 passed, including temporary bidirectional counter coverage.
• Tracked diff contains only src/Hook.sol.
• git diff --check: clean.

Implemented comprehensive Foundry coverage in test/Hook.t.sol.

Coverage includes:

• Exact-input and exact-output swaps in both directions
• Per-pool counter isolation
• Zero-liquidity behavior
• Zero delta and fee override
• Liquidity and donation behavior
• Unauthorized callbacks
• Zero-amount and post-callback failure rollback
• No assets retained by the hook

Verification:

• forge build — passed
• forge test — 18 passed, 0 failed
• Only test/Hook.t.sol was modified
• No untestable defects found; no findings file created

Findings written to .imd-findings.json. Repo files untouched (git status --porcelain is empty; all experiments ran in an out-of-repo scratch project at /tmp/imd-scratch remapped to the vendored libs).

What I checked

Baseline: forge build + forge test — 18/18 pass. The implementation itself is correct: key.toId() matches PoolManager's id derivation, the (selector, ZERO_DELTA, 0) return is inert on both static- and dynamic-fee pools, onlyPoolManager is inherited, and adding/removing liquidity and donations don't touch the counter (all verified by probe).

The defects are in the tests and the docs.

Findings, ranked

1. medium — three of the four negative counter tests cannot fail (test/Hook.t.sol:146). test_FailedSwapRollsBackTheIncrement, test_ZeroAmountSwapRevertsWithoutIncrementing, and the trailing assert in test_RejectsDirectBeforeSwapWithoutIncrementing assert swapCount == 0 after a vm.expectRevert'd external call — an EVM guarantee, not hook behaviour. Proved by mutation: swapCount[key.toId()] += 1000 fails 4 tests and all three of these still pass. The zero-amount one is doubly inert — the -vvvv trace shows PoolManager.swap reverting at its amountSpecified == 0 guard (PoolManager.sol:193) with no beforeSwap frame at all.

2. low — the counter counts non-reverting swap attempts, including zero-value ones (src/Hook.sol:66). Ten swaps of 1 wei give swapCount == 10 with 0 token out (~66k gas each). The suite enshrines this rather than flagging it: the zero-liquidity test asserts both deltas are 0 and the count is 1 in the same breath.

3. low — enabling the flag re-tiers the pool 0% → 0.30%, untested and unremarked (src/Hook.sol:50). BaseHookTest.poolFee() switches from dynamic-fee to STATIC_FEE once any permission is set. Measured: the same 1 ETH buy returns 982962843890629663540983 before vs 980016845319393782174247 after — 0.2997% worse. The hook takes no fee, but nothing pins slot0.lpFee, so the suite can't distinguish the two causes.

4. low — the contract NatSpec contradicts the code (src/Hook.sol:14). Still says "no behaviour" and "Every permission below is false, so the pool calls into this contract at no point," directly above beforeSwap: true and a per-swap storage write.

5. low — the dynamic-fee path is never exercised through the PoolManager (test/Hook.t.sol:76). Hooks.sol:263 only reads the hook's uint24 return when the pool is dynamic-fee; every pool the suite builds is static. A OVERRIDE_FEE_FLAG | 500 regression would only be caught by the one direct-call assertion. Same for remove-liquidity and non-empty hookData — verified correct today, but unguarded.

6. info — test_RejectsCallbacksFromAnyoneButThePoolManager passes for the wrong reason (test/Hook.t.sol:56, pre-existing). Bare vm.expectRevert() on beforeInitialize, which reverts HookNotImplemented() even when pranked as the manager — confirmed by trace. The new test_RejectsDirectBeforeSwapWithoutIncrementing already uses the correct selector-matched form.

Done. launch.json is the only file added (git status shows just ?? launch.json), forge build compiles and all 18 tests in test/Hook.t.sol pass.

What the manifest says

• Description — the hook counts swaps: beforeSwap only, one increment per swap per pool in either direction (exact-input and exact-output), read back via swapCount(PoolId). It records explicitly that nothing else changes: no fee, zero BeforeSwapDelta, no fee override, no return-delta flags, and liquidity/donation/zero-liquidity paths untouched because no callback for them is enabled.
• Contracts — hook Hook (src/Hook.sol, on BaseHook, constructor(IPoolManager)), token LaunchToken (src/LaunchToken.sol, ERC20).
• Permissions — all 14 Hooks.Permissions fields, copied against src/Hook.sol:44-60: beforeSwap: true, every other field false. I compared them field-by-field; test_EnablesOnlyBeforeSwapWithoutReturnDeltaPermissions pins the same thing on-chain (flagsOf(...) == BEFORE_SWAP_FLAG).
• Pool — the launch pool: currency0 native ETH (address zero), currency1 LaunchToken, fee: 3000, tickSpacing: 60, hooks Hook. Fee 3000 is correct now rather than the dynamic-fee flag, because BaseHookTest.poolFee() switches to STATIC_FEE as soon as the hook declares a flag.

No supply, ownership, allocation or price field is present anywhere in the file — the starting tick was deliberately left out on those grounds, since it is a price.

One caveat worth stating plainly: there is no launch manifest schema in this repo, its git history, or the fetched remotes (dep0/dep1 carry only the src/Hook.sol and test/Hook.t.sol commits), so I could not validate against the schema mechanically. The shape above is derived from the task's own instructions — name the hook and token contracts, the declared permissions, the pool — using v4's exact Hooks.Permissions key names so a field-by-field comparison against getHookPermissions succeeds. If the network's schema fixes different key names or nesting, that is the part most likely to need adjusting; the facts it asserts are verified.