# Amazon purchase comparison — validation

Final report reviewed November 11, 2026. AgentChat room: Amazon (`chat-6cdvm1yw`).

## Reviewed artifacts

- `mythic-amazon-savings.html` SHA-256: `31638bdd86036a310564ac1f477c5b0eda3280cf2cfb9c71e7d921904587bb2e`
- `comparison-data.json` SHA-256: `207ed228962baa6542066bdca6ed7ad32468f8d23f99f86fe60616ae4507e39d`
- Exact source hashes are embedded in both files. The five source JSON files are supplied alongside the report.

## Findings

93 distinct original products, excluding Sparkling Ice. Completed purchases: 173 CSV rows, 261 original packs, $4,238.31 item subtotals. Recorded completed net payments were $4,362.60, a different basis that includes taxes, shipping and promotions. Pending purchases (3 packs, $48.46 item subtotals) are excluded from the scenario.

Main: 29 options reduce historical item costs by $843.35 (19.90%), yielding $3,394.96. Category reductions: water/soda $417.21; energy/hydration $357.38; pantry $41.32; snacks $27.44.

Higher-caffeine opt-ins: 18 products, adding $112.62 beyond the best main choices. Combined reduction $955.97, scenario $3,282.34. Overlapping options replace each other; savings are never counted twice. The legacy JSON keys `generic` and `optional_name_brand_savings_alone` remain for compatibility: `generic` means the main any-brand option; the latter is $344.51 in full historical savings on opt-in rows, NOT an additional saving. Use $112.62 for the incremental opt-in amount.

All main and opt-in calculations were independently recomputed: original baselines match source JSON; replacement cost = whole packs × current price; saving = historical item subtotal − replacement cost; sufficient individual count and total weight/volume. Butter is compared by ingredient weight: 24 half sticks become 12 full sticks with equal 48oz total. Cutting is required. Tea uses original listing Item Weight (8.1oz), not an independently verified net-content label; two replacement boxes provide 16oz net and 200 bags versus 120 original bags.

The main selected offers showed no sale/reference signage when observed. This does not establish permanent standard prices. Discount-dependent Slim Jim and Dr Pepper Zero offers show current and exact “Typical price” references separately and are excluded from main savings. No subscription, coupon, bundle or quantity discounts assumed. Creamer and other amount-unverified candidates remain held. Main energy alternatives match stated caffeine amounts; different flavors/formulations remain disclosed. The 270mg options are separate.

## Independent review

- First Codex participant, Codex Pantry Analyst, generated the deduplicated JSON. Claude Opus and Synth Claude independently validated it against the cleaned purchase CSV (room #32 and corrected #40).
- Claude Opus final acknowledgment #148: exact final HTML/data hashes PASS; 93 baselines, all main/opt-in math, source hashes, embedded JSON, rendered headline/table/copy checked. No blocking findings. Live Amazon pricing and availability were not independently checked by this reviewer.
- Codex Pantry Analyst final acknowledgment #147: exact final hashes PASS; source versions, embedded JSON and copy fixes; prior full quantity/cost/baseline review #138 remains applicable.
- Synth Claude full assembly review #140: all calculations PASS, 47 recommendation/opt-in cards, 31 main historical table rows and 93 full-cost rows; zero JavaScript errors. All 103 unique image URLs in that candidate loaded. Final acknowledgment #149 repeats the checks on the exact final hashes: all math and source hashes PASS, 103/103 image URLs load, no overflow at 1024px, no blocking findings.

## Browser and file checks

Codex Cedar checked the final report in the user's supplied Chrome session. Filters returned 93 all-products rows, 2 Gorilla results, and 28 snack originals. Final default has 29 recommendation cards, 31 historical table rows (29 + retained originals + total), and 93 full-cost rows. Final embedded JSON equals the companion data. JavaScript syntax check passed. Final visible text has no stale main “no verified candidate” reasons or “none on selected offer” wording. Direct 390px viewport check: document width 390px, no page overflow; table scrolls within its container. Normal viewport restored.

92 of 93 original photos were recorded. The creamer original listing returned 404, so it has an honest missing-image placeholder. Replacement/held photos are included where verified. Photos load from Amazon and require internet; they can change with the listing. This is a historical item-cost replay at observed current prices, not a checkout quote or proof those prices existed on historical dates. Unresolved products retain historical cost; the bounded search does not prove that no cheaper option exists.