Dune price mirror: staging evidence (2026-07-20)

Permanent audit record for the PR "feat: Dune price mirror + coherent market marks (drop DeFiLlama from the mark pipeline)". Companion to dune-price-mirror-plan.md (Phase D acceptance). This page is deliberately NOT in the docs navigation; it is a frozen record of the staging validation. Every figure below was produced on the staging DB after the shadow backfill, the token_basis parity swap, and the two guarded mark-repair runs.

Evidence summary

Phantom-wallet acceptance (corrected)

The original plan target of +0.05 ± 0.02 ETH assumed both wrapper legs sat at par at the entry block. That assumption was wrong. A block-precise Curve NG round-trip mid at entry block 25407156 shows weETH at −4.5bp (wstETH slightly rich), so the TRUE entered basis is ≈ 0.00 ETH, not +0.05. The repaired app path now reports −0.021 ETH through the app's own deriveLegEnteredBasis on the re-marked rows, each leg reconstructed within 0.9bp of the on-chain pools:

Leg	Mirror-derived (bp)	On-chain pool (bp)	Divergence (bp)
weETH	-3.96	-4.49	0.53
wstETH	-0.70	-1.59	0.89

Corrected, falsifiable acceptance criterion: per-leg mark within ~1.5bp of block-precise pool truth. PASSED. The old -0.82 ETH disease is gone.

Deepest 1-year discount marker on the wrapper depeg charts (client-rendered, verified in a real Chrome via CDP, not SSR grep):

Token	Before (old feed)	After (mirror)
wstETH worst-1y	-2.08%	-0.78%
weETH worst-1y	-1.02%	-0.81%

The old markers tagged DeFiLlama cross-vintage feed artifacts; the mirror markers track real dislocation.

On-chain spot-check (5 wrapper flow rows vs pool reads at their own blocks)

#	Token	Block	Mirror vs pool
1	wstETH	25407156	0.89bps
2	weETH	25433939	0.28bps
3	wstETH	25484121	1.82bps
4	weETH	25534325	0.41bps
5	wstETH	25563279	0.08bps

All five are within the "a random sample of wrapper flow rows re-verified within a few bps" acceptance criterion (row 3 at 1.82bps is the widest, still a few bps).

Repair idempotency

Phantom wallet: 61 flow rows and 263 snapshot rows were re-marked on the first --execute. A second --execute reports 0 rows to update: the isMaterialChange write-gate holds because the same stored (already-descaled) amount multiplied by the same standing mirror bar re-derives the identical value_market (sub-EPS_REL, no write). value_redemption was never touched.

syrupUSDT: corrupt Dune bars, excluded from the swap

The Dune hourly mirror for syrupUSDT carries corrupt USD bars over 2025-07 through 2025-10: stuck plateaus ranging $0.067 to $6.36 for a token that trades near $1. These drive the parity report's 298x step-noise blow-up and the 47,846bp max offset below; they are source-query ingestion artifacts, not real price. Decisions:

syrupUSDT is excluded from the token_basis swap (its shadow rows are deleted before the swap runs).
997 corrupt bars were purged from the mirror under the same [0.8, 1.5]x sanity criterion used for share-rate cleaning.
The syrupUSDT share_rate series is clean (the redemption side is unaffected).

This class exposes a real gap: USD-book marks are a single quote and lack the same-bar numerator/denominator cancellation that protects the ETH and BTC books, so a stuck USD print is not self-cancelling. The ingest-guard design (a redemption-band check vs a stuck-price detector) is left as a decision for Fred (see the PR's Known limitations).

DeFiLlama one-print artifacts confirmed (old feed, flat in the mirror)

Two of the deepest old-series discounts are confirmed DeFiLlama single-print artifacts, flat in the mirror at the same bar:

sUSDe / USDe, 2026-02-02: the old series prints -210bps (USDe -210.35, sUSDe -208.65) at a single 6h bucket. The mirror reads roughly -9.5bps (USDe) / +2.3bps (sUSDe) at that bar. A one-print feed spike, not a peg break.
USDtb, 2025-11-16: the old series prints -38.90bps at a single bucket; the mirror reads +6.28bps (no dislocation). A one-print feed artifact.

Both match the previously-diagnosed token_basis noise floor (the 6h step at the i.i.d. noise floor).

Full parity report (verbatim)

token_basis parity: served vs Dune-mirror shadow

Generated 2026-07-20T04:49:39.955Z. Per token, over the window where both series exist. Values in basis points (bps) unless noted. No pass/fail threshold is applied; the numbers are for review.

Summary

Token	Num	Old step-noise	New step-noise	New/Old	Skipped 6h (old/new)	Mean abs offset	Max abs offset	Old rows	New rows	Matched	Extremes survived
sUSDe	USD	10.07	9.67	0.960	3/0	20.38	218.13	1304	1460	1304	0/5
sUSDS	USD	3.86	3.09	0.801	5/0	5.13	51.64	1298	1460	1298	1/5
syrupUSDC	USD	5.08	7.43	1.464	71/0	5.50	141.76	1372	1460	1372	5/5
syrupUSDT	USD	7.20	2147.96	298.324	3/1	1374.54	47846.53	1173	1161	1158	5/5
reUSD	USD	25.09	9.15	0.365	6/0	19.62	636.63	1429	1460	1429	5/5
wstETH	ETH	19.75	3.36	0.170	0/0	7.41	191.93	1460	1460	1460	5/5
weETH	ETH	12.78	4.17	0.326	0/0	5.22	84.16	1460	1460	1460	5/5
rETH	ETH	15.94	5.31	0.333	0/0	7.10	80.43	1460	1460	1460	5/5
osETH	ETH	65.30	65.33	1.000	5/0	30.87	1732.55	1449	1460	1449	5/5
ezETH	ETH	11.85	7.86	0.664	2/0	6.07	110.43	1454	1460	1454	5/5
GHO	USD	3.23	3.11	0.963	0/0	4.42	22.78	1460	1460	1460	5/5
USDe	USD	9.42	2.26	0.240	0/0	4.84	202.92	1460	1460	1460	5/5
USDtb	USD	11.42	4.65	0.407	1/0	5.60	212.48	1459	1460	1459	2/5
WBTC	BTC	15.09	3.94	0.261	0/0	8.32	50.06	1460	1460	1460	5/5
cbBTC	BTC	9.78	2.67	0.273	0/0	4.78	67.72	1460	1460	1460	4/5
USDC	USD	0.74	0.71	0.957	0/0	0.99	3.36	98	98	98	5/5
USDT	USD	1.30	1.21	0.932	0/0	0.70	2.97	98	98	98	5/5
DAI	USD	n/a	n/a	n/a	0/0	n/a	n/a	0	0	0	0/0

Step-noise is the population stddev of basis deltas between snapshots EXACTLY 6h apart; wider gaps (daily pre-2025 history, refresher outages) are skipped and counted ("Skipped 6h").

Per-token discount extremes

Survives = the shadow series shows a same-sign (discount, basis < 0) point within ±1 snapshot (6h) of the old extreme. A non-survivor is an old-feed artifact CANDIDATE (surfaced, not a verdict).

sUSDe (USD)

Overlap 2025-07-20T06:00:00.000Z .. 2026-07-20T00:00:00.000Z; old rows 2597 (overlap 1304), new rows 1460 (overlap 1460), matched 1304.