The findings file is in place and the working tree holds nothing else of mine. The build output directories are gitignored and the scratch directory is deleted.

Result: no critical, high or medium defect in DerbyAuction. The review is written to .imd-findings.json as five info entries: one coverage statement and four trust notes, each with a concrete state and the expected versus actual outcome.

What I read and checked

• Read in full: src/DerbyAuction.sol, the ISwarmDerby surface of src/SwarmDerby.sol, both test files, the WP3 spec and DEPLOY.md. forge test passes 94 of 94 on Forge 1.8.3.
• Walked every state-changing function against the Pashov checklist: math, access control, reentrancy, flow ordering, boundaries, invariants and the launch-forbids list. Effects precede interactions everywhere, every token-moving path is reentrancy guarded, the balance invariant holds through failed sends, and veto and payBonus are provably mutually exclusive in time.
• Replayed the protected harness opcode scan on the compiled runtime. It is 9,520 bytes with no DELEGATECALL, CALLCODE or SELFDESTRUCT, and the constructor makes no external call.
• Verified the constructor inputs on Robinhood Chain over RPC. Both addresses hold code, the deployed SwarmDerby's imd() returns the IMD address the brief names, and its runtime bytecode is byte-identical to a local build of the repo's source once the IMD immutable is masked.
• Ran a fork test with the exact launch arguments against the real IMD token. Bid, outbid refund, settle and veto all moved the exact amounts, so the strict transfer and return-data handling works with this token.

What could not be reached

• The IMD token's source. The Blockscout API returned HTML to this host, so its owner powers are taken from DEPLOY.md.
• payBonus on the fork, because Forge 1.8.3 has no ArbSys precompile on a forked chain. The unit tests cover it with the etched mock.

Trust notes recorded (all info)

• A vetoed or reclaimed winner gets the bid less the build fee, and the owner controls fee, studio and veto. Zero impact at the launch fee of 0, and documented.
• Carry has no exit if auctions stop or every later winning day settles late. Design choice mirroring SwarmDerby's rollover.
• A top-3 winner the token refuses to pay loses the prize to carry with no credit, unlike bidders and the studio. Documented and ABI-bound.
• The IMD token owner can block or pause transfers, which halts the auction for the duration without losing funds.

The accepted items in the brief (extensions stop at 19:00 UTC, settle reads the fee and studio at settlement, the payBonus and reclaim race) behave as stated and are not reported as findings.

Added ADAPTATION.md with exact launch arguments, audit dispositions, and verification evidence. Contract code and ABI remain unchanged.

• forge build passed.
• All 94 project tests passed.
• Five scratch checks passed, including empty-chain CREATE2 deployment.

Live RPC checks returned HTTP 403; that limitation is documented. No live deployment was performed.

Created launch.json for DerbyAuction only, using the exact approved constructor arguments.

Validated the manifest structure and compiled constructor ABI. forge build succeeded; all 94 tests passed. No other files changed.

Added failure-path tests, 1,000-run fuzz properties, and random-sequence invariants in DerbyAuction.invariant.t.sol.

forge build succeeds; forge test passes all 101 tests. Only the new test file was added. Live Robinhood Chain integration remains unverified.

The findings file is in place and the harness excludes it from git by design. No tracked file changed.

Review complete: no defects found in DerbyAuction; one informational trust note recorded.

What I covered

• Traced every DerbyAuction entry point for the Execution Trace, Periphery and First Principles failure modes: wrong-state execution, partial state updates, stale reads, sentinel paths, external return handling, and each implicit assumption in the day arithmetic, carry accounting, refund credits and reentrancy guards. All hold.
• Confirmed the four audit fixes behave as the spec says: reclaim grace from the later of theme-day end and settlement, no carry on late settlement, credited studio fee, and openDay naming an extended day.
• Ran five scratch probes under test/scratch/ for cases the suite does not state directly: two auctions open at once during an extension, the carry boundary at midnight with veto returning carry, an absent derby, self-raise net flow, and studio equal to leader. All passed as the code intends.
• Verified the live periphery on Robinhood Chain, since the RPC answered this time. The token at the pinned address is an OpenZeppelin v5 ERC20 and not a proxy. Its transfer returns exactly 32-byte true with no fee, so the strict 32-byte acceptance rule and balance-delta check match it. The derby at the pinned address has code, points at the same token, and its board and dayClosed reads decode as the auction expects.

The one note is informational. The live IMD token is a LayerZero OFT whose owner can block addresses and disable transfers. Today transfers are enabled and nothing relevant is blocked. If that changes, the auction's documented failure handling applies: a blocked winner's prize becomes carry with no credit, and a blocked auction address stalls bids and tips until unblocked. That is an external trust assumption, not a code defect, and no unprivileged actor can trigger it.

Coverage record has 25 rows: all 22 listed entry points, the constructor arguments, and two invariants. Every DerbyAuction row is holds except payBonus, which references the informational note. The SwarmDerby rows are holds, with swing, finalize and settleNextDay traced for the auction's dependency on a board that is final once dayClosed is true.

The full suite still passes at 94 tests. No critical or high finding exists, so no proof test is attached and the code should ship unchanged.

The review is complete and written to .imd-findings.json. No file under src/, test/ or configuration was changed, and the scratch directory is removed.

Outcome: no critical, high, medium or low defect in the Access Control, Trust Gap or Asymmetry areas of DerbyAuction. One informational trust item is recorded.

What I checked

• Permission map. Owner holds veto, setStudio, setBuildFee and transferOwnership. Only the pending owner can accept. Everything else is permissionless by design. No storage variable has a weaker writer than its guarded sibling. Ownership comes from the explicit owner_ argument, not the factory's msg.sender, and cannot be renounced.
• Asymmetry pairs. Veto and reclaim mirror each other: both zero the bonus, return bonus - carryIn to the leader and restore the carried part to carry. Settle's winner and empty branches, and its before-midnight and after-midnight carry branches, were diffed. Every storage variable has matching writers and readers, and the conservation invariant holds through all of them.
• Trust seams. The payBonus tip is bounded and only paid on a non-empty board. Permissionless settle timing cannot be blocked by an outsider, so the carry decision cannot be forced against the honest party. The owner's only in-flight lever is the fee and studio read at settlement, which the task accepts.
• Constructor and dependencies, verified live on chain 4663. The token address holds code, reports symbol IMD with 18 decimals. The derby address holds code, its imd() returns that token, and currentDay, dayClosed and board answer with the shapes DerbyAuction calls.

The one recorded item (info). With studio set to the owner and the fee cap at 1 IMD, the owner can raise the fee after bids were placed, let settlement run, then veto. The winner gets back their bid less 1 IMD while no theme is built. Reproduced with a scratch test against the current tree. It is owner-only with no unprivileged amplifier and is already documented as an owner trust assumption, so it needs no code change under the agreed design.

Coverage. All 22 listed entry points have a row, plus rows for the constructor arguments and the balance-conservation invariant. All DerbyAuction rows are holds except setBuildFee, which points at the info item. The SwarmDerby rows are marked holds as out of the assigned area and unchanged, since DerbyAuction only reads its views.

Review complete. The findings file is at .imd-findings.json with two informational entries and a 27-row coverage record. No source files were changed; the only other file I created is the scratch test under test/scratch/, which is not kept.

Result: no critical, high, medium or low defect in the Economic Security, Invariant or Flow Gap areas. Every DerbyAuction entry point traced clean, and the full suite passes (94 tests, 0 failed).

What I verified:

• Conservation holds across bid, settle, veto, payBonus, reclaim and withdrawRefund, matching the project fuzz invariant. Veto and reclaim return only the bid less fee, never inherited carry.
• Carry ordering is deterministic. The settle-before-theme-day windows of consecutive days never overlap, so carry cannot be raced between two auctions. A scratch test confirms day D+1 cannot be settled while day D can still take carry.
• Payout finality. Once SwarmDerby reports the day closed, any late reveal is a foul, so the board payBonus reads cannot change. A winner has no way to make their own bonus unpayable to force a reclaim.
• Live periphery. The derby at the brief's address has runtime bytecode identical to this repo's build except for the immutable IMD address, its token matches the auction's imd_, and dayClosed works on chain through ArbSys. Earlier reviews could not reach the RPC, so this is new evidence.

The two informational entries:

1. Carry capture by a minimum bid. Once carry has accumulated from empty or short boards, a 2 IMD bid on a quiet day plus three self-owned arcade wallets collects the whole pool. The reproduction shows 152 IMD received for a 2.45 IMD outlay. This is the documented known limit about bots playing the arcade, amplified by carry concentration. Any mitigation would change the payout math the brief forbids changing, so it is recorded, not proposed as a fix.
2. IMD blocklist dependency. The live token has an owner-controlled blocked(address) and no pause, fee or proxy. The auction already handles a blocked bidder or winner. If the auction contract itself were blocked, all its IMD would freeze until unblocked. External trust assumption, now with on-chain evidence.

Accepted items (19:00 extension cap, settlement-time fee and studio, post-grace race) were traced and left out of the findings as instructed.

The review is complete. The findings file is in place and the only other new files are under test/scratch, which the harness excludes and deletes.

Outcome: no critical, high, medium or low defects in the math of DerbyAuction. One info-level boundary note is recorded. The code should ship as it is.

What I checked in the assigned area

• Fixed-point math. The basis-point helper is exactly floor(amount × bps / 10000) with no overflowing intermediate. The minimum next bid equals max(2 IMD, ceil(lead × 1.05)) for every lead whose product fits in 256 bits, fuzz-verified over 3000 runs including 0, 1, 9999, 10000 and 10001.
• Bonus split. Tip plus the three shares plus the carried remainder always equals the bonus, for bonuses from 1 wei to the uint256 maximum, boards of 0 to 5 players and any pattern of failed sends. Dust is at most 3 wei and goes to carry. The bonus is always at least 1 IMD because the fee cap is below the minimum bid, so no share can round to zero.
• Subtractions. Every subtraction (end minus now, amount minus fee, bonus minus tip, bonus minus carryIn) has its bound enforced on the path before it. Veto and reclaim return exactly the winner's own net bid and send carryIn back to carry, fuzz-verified.
• Time boundaries. The bid window, the carry cutoff in settle, the veto cutoff and the reclaim grace all sit on the same day arithmetic. The anti-snipe end never moves backwards and never passes 19:00 UTC. For every timestamp from 64800 to 2^62, with and without an extension of the previous day, openDay names a day whose window contains now.
• External boundaries. Token calls handle no-code, false-return, void-return, malformed-return and zero-amount cases without blocking other recipients. The derby's reveal window and its dayClosed use the same inequality, so the board payBonus reads is final.
• Target chain. Reads against the public Robinhood Chain RPC confirm chain id 4663, the derby address has code and reports the IMD token address, and the token has symbol IMD with 18 decimals, matching the contract's constants.

The one note. Before the chain's first 18:00 UTC, openDay returns day 1, which auction and bid reject with BadDay. This is unreachable on the live chain and affects no funds. It is recorded as info with a reproduction, and no change is recommended given the frozen ABI.

Coverage record. All 22 listed entry points have a row, plus rows for openDay, minNextBid, the bps helper, the balance conservation invariant and the constructor arguments. The project suite passes with 94 tests. Not reached: no fork test against the live derby, and the real token's transfer semantics were only checked by symbol and decimals reads.

Review complete. No tracked file changed; .imd-findings.json holds five informational findings and a 25-row coverage record.

Outcome: no critical, high, medium or low defect in DerbyAuction. The fix commit for the earlier medium and three lows is correct, and every specialist finding reproduced only as documented, accepted behaviour.

What I verified:

• Fix commit. Reclaim grace from the later of theme-day end and settlement, late settle takes no carry, unsendable studio fee is credited, and openDay names the extended day. Each traced in source and covered by the existing regression tests.
• Test suite. The full suite passes with 101 tests: 40 auction, 54 SwarmDerby, and 7 from the independent tester's invariant and boundary file. The invariant run completed 256 runs and 16,384 handler calls.
• Live dependencies. On chain 4663 the IMD token reports symbol IMD, 18 decimals and transfers enabled. The derby at the brief's address returns the same token, a board size of 10, and working board and dayClosed reads. Its runtime bytecode is byte-identical to a local build of this repo's SwarmDerby source with immutables masked.
• Deployability. DerbyAuction's runtime uses PUSH0 and MCOPY. An eth_call probe on the live RPC executed MCOPY, TSTORE and PUSH0 successfully, while an INVALID probe errored, so the chain supports the Cancun bytecode. The runtime has none of the forbidden opcodes.
• Manifest. launch.json lists the five constructor arguments in order with the brief's exact addresses, $owner for owner and studio, and fee zero.

Findings kept, all informational and each reproduced in test/scratch/Review.t.sol:

1. Live IMD token owner powers (merged from audit_flow and audit_economics). A blocked winner's prize goes to carry, a blocked auction address freezes bids, tips and withdrawals until unblocked. Verified live that the token exposes blocked and transfersEnabled.
2. Fee raised after bids then veto (audit_permissions). Studio keeps the fee, winner gets bid less fee. Accepted owner trust, launch fee is zero.
3. Carry captured by one minimum bid on a quiet day (audit_economics). Reproduced with real swings: 152 IMD received for a 2.45 IMD outlay. Property of the accepted payout math.
4. openDay returns day 1 before the first 18:00 UTC (audit_math). Unreachable on mainnet.
5. My own note: setStudio to the auction's own address strands the fee as a self-transfer owed to nobody. Owner-only, capped at 1 IMD per auction.

Coverage: all 22 entry points marked holds with reasons, plus rows for the conservation invariant, the manifest, and Cancun deployability. No proofs attached since nothing reached critical or high.