The route under investigation

Quote-Execution Mismatch in Tempo Multi-Hop Swaps

The question: Can a swap system fail to estimate a route that would execute successfully and therefore be unable to compare it with other routes? We tested route lengths, hook types, input amounts, and liquidity conditions. For certain inputs on cUSD → PathUSD → USDT0, V4Quoter returns no quote even though a fork transaction succeeds when input is prepared first.

cUSD

→

Pool 1Tempo hook
cUSD / PathUSD

→

PathUSD

→

Pool 2Tempo hook
PathUSD / USDT0

→

USDT0

How the two paths diverge

The affected quote simulation can reach the hook before the required input balance is prepared. A funded transaction supplies the input first, then runs the same route.

Quote simulationStops with no quote

1Start simulating cUSD → PathUSD → USDT0.
2The first Tempo hook asks PoolManager to transfer cUSD.
!Input is not prepared. The token transfer reverts here.
4No output amount is returned for route comparison.

Funded executionCan complete

1Transfer the user's cUSD into PoolManager first.
2Input is prepared. The hook's transfer succeeds.
3Run both Tempo conversions through PathUSD.
4Transfer USDT0 to the recipient.

No quoteThe simulation stopped before returning an amount.

Not a wrong quoteThere is no quoted amount to compare with execution.

Not proof of no liquidityA separately funded execution can still complete.

What we tested

We varied route length, hook placement, input amount, and liquidity to separate possible explanations:

Cases	Purpose	Reported result
01-02: Ordinary pools, one and two hops	Is multi-hop routing itself the cause?	Quotes match execution.
03: Two fee hooks	Does the quoter skip custom hooks?	Both hooks run; quote matches execution.
04-05: Tempo-style hook first versus last	Does token availability at the hook matter?	The first-hop case fails without prepared input; the last-hop control works.
06-08: Deployed Tempo pools, small inputs	Do all real Tempo routes fail?	The documented small-input routes work.
09-10: Input above PoolManager's cUSD balance	Can funding order explain a failed quote?	V4Quoter fails; funded execution completes.
11: Extremely large input	Can we distinguish this gap from genuine illiquidity?	Both quote and execution reject the swap.

Experiment cases

Open a case to see the full path, input and starting balance, quote, funded execution, and interpretation.

Controlled casesCases 01-05

Tempo fork casesCases 06-11

What the evidence supports

For certain multi-hop Tempo routes, the examined UniRoute quote path can fail to prepare the balance required by hook execution. An executable route may therefore have no usable quote for route comparison. A fix must produce both an accurate quote and a compatible funded execution plan.

This dashboard does not claim measured production impact, user loss, or better prices. Those claims require production traffic data and same-block comparisons against other executable routes, including gas.

Implemented and validated on a pinned Tempo fork

Recover the quote. Prove the execution. Admit only when both match.

For verified Tempo routes, the new path quotes each hop at the same block, builds the funded transaction, validates the complete Universal Router execution, and only then adds the route to comparison.

Tempo chain 4217Block 41,183,156Exact inputFail closed

Recorded Anvil fork experiment

Three inputs. Before and after QuoteBridge.

These are measured results from three independent runs at the same Tempo block. Select a case to inspect its quote, funded transaction, and receipt. No local setup is needed to view the results.

Saved fork measurements Anvil 1.8.3 27 Sep 2026 UTC
Tempo block 41,183,156

Choose a measured case

The route and fork block stay the same. Only the cUSD input changes.

25 cUSD→Tempo pool 1→PathUSD→Tempo pool 2→USDT0

Before · standard V4Quoter No quote

V4Quoter could not return an amount.

After · QuoteBridge + funded Router 24.997499 USDT0

The recipient received the quoted amount.

Before: V4Quoter quote

The existing quote path's result for this input.

Recorded

V4Quoter result—

Loading the recorded result.

After: QuoteBridge quote

Each Tempo hook is quoted in route order at the same block.

Recorded

QuoteBridge result—

The output of the first hook becomes the input of the second.

Funded planPrepare input → swap → deliver outputSETTLE → SWAP_EXACT_IN → TAKE

After: funded execution

The complete Universal Router transaction was sent on the local fork.

Recorded

Transaction status—

Recipient received—

Receipt gas—

Loading the recorded receipt.

Did quote match what arrived?

Compare QuoteBridge's output with the recipient's USDT0 balance change.

Recorded

QuoteBridge quote—

Actual received—

Difference—

Loading the recorded comparison.

Recorded evidence · fork snapshot restored for each case

The admission pipeline

A quote is a candidate, not a result.

Select a step to see what the boundary proves before a Tempo route becomes eligible.

STEP 1

Accept only a verified route shape.

The dispatcher checks the Tempo hook deployment, pool IDs, token direction, fee, tick spacing, chain, and pinned block before using the specialized path.

Guard Unknown hooks and unsupported route shapes never fall through to this quote path.

Any failed guard exits hereunsupported routemissing validatorexecution revertwrong outputwrong block or planNot admitted

Previously recorded fork proof

25 cUSD: from no quote to validated comparison input

25.000000 cUSD→PathUSD→24.997499 USDT0

Standard quoteno quotefirst hook transfer reverts

Recovered candidate24.997499USDT0

Executed output24.997499USDT0

Receipt gas316,216gas units

Hook calls2both route hops

Admissionvalidatedadded to comparison

Direct hook quotes compose the candidate at the pinned block.

The plan transfers input before the hooks request it.

The recipient's USDT0 transfer equals the candidate exactly.

Route, amount, block, and complete plan are bound before admission.

{
  "quotePath": "tempo_hook",
  "quoteStatus": "candidate",
  "validationStatus": "validated",
  "amountIn": 25000000,
  "amountOut": 24997499,
  "gasUsed": 316216,
  "hookCalls": 2,
  "planDigest": "f5d7fcf6...f598"
}

A second validation trap

Gross swap output is not always the wallet increase.

Tempo can charge transaction gas in PathUSD. The validator reads the receipt instead of treating the smaller wallet delta as a bad quote.

Gross swap output0.999800PathUSD

Wallet increase0.999479PathUSD

Receipt-proven gas0.000321PathUSD

Same payer and recipient999,800 gross transfer

Wallet rises by 999,479 because the receipt charges that wallet 321 PathUSD gas.

Separate recipient control999,800 received in full

The payer separately pays 332 PathUSD gas, proving the swap output was not reduced.

✓

No fixed 321-unit adjustment. Gas is reconciled only when the receipt proves the fee payer, token, collector, and amount.

Fail-closed routing

What is allowed into comparison?

Observed state	Decision	Why
Quote and complete execution match	Admit	The candidate is executable as quoted.
Candidate exists, but no validator is available	Keep out	A number alone is not execution evidence.
Executed output differs from the quote	Keep out	The candidate failed validation.
Route, input, block, or plan differs	Keep out	Evidence belongs to another execution context.
Output-token gas cannot be proven	Indeterminate	Ambiguous token flow is not admitted.
Tempo Exchange reports insufficient liquidity	Reject	Funding order cannot repair real illiquidity.
Ordinary no-hook route	Standard path	It stays with the normal quoter.
Unknown custom hook	Unsupported	It is never silently promoted.

Regression protection

What the tests protect

✓ Quote recovery✓ Full Router execution✓ Route and amount binding✓ Block hash binding✓ Plan digest binding✓ Gross-output verification✓ Output-token gas reconciliation✓ Separate-recipient control✓ Genuine-liquidity rejection✓ Missing-validator rejection✓ Output-mismatch rejection✓ Unknown-hook rejection

$python -m unittest discover -s tests -vguard suite covered

Integration boundary

Implemented proof, explicit production boundary.

RoutingUniRoute strategy

→

Public contributionTempo dispatch patch

→

Required boundaryPlan + validator

→

Measured proofUniversal Router fork

Implemented

Runnable standalone dispatcher
Public UniRoute dispatch patch
Full Router validation for supported routes
Receipt-based gas reconciliation

Still required for production

Private service must inject the real boundary
Arbitrary blocks and hook deployments remain unsupported
No measured better-price or user-impact claim
No claim of production deployment

We do not admit a route because we found a number. We admit it only when the same bound execution plan proves that number.