How the math works

Every number this product shows is computed from a cited source or labeled as an assumption. This page is the audit trail.

Parsing: propose, never guess

List parsing proposes a structured reading and routes every ambiguity to you. Nothing persists until you confirm it, and unresolved lines stay out of the math.

Net-required math

Requirements merge across children by product and variant; usable inventory subtracts; what remains is what you buy. The subtraction renders as written arithmetic so you can check it.

Landed cost and the frontier

A basket's cost is items plus tax plus shipping per store trip. We return every undominated option across cost, stops, delivery time, and confidence. Collapsing that into one winner would mean hiding a trade-off, so we refuse.

Trend evidence

A trend label requires at least 3 of 5 independent signal families to pass minimum evidence thresholds with organic (not paid) signal. Below that, the honest label is "not enough evidence" — and that is the default.

When we refuse to show a number

Suppression beats guessing. These triggers hide or downgrade output, each with its reason shown in place of the fact:

• This list is stale or not yet confirmed, so its items render as unverified.
• This product's exact variant is not confirmed, so we are not counting it toward your total yet.
• This price or stock reading is older than our threshold, so it is hidden or flagged.
• Not enough independent evidence to call this trending, so no trend label is shown.
• We cannot confirm this school policy from an official source, so the policy filter is off.
• This product matches a recall or is under safety review, so it is excluded.
• A retailer-fed value conflicts with a neutral source, so we show neither until they agree.
• This option cannot meet your deadline with confidence, so it is flagged.

Provenance on every fact

Every rendered fact carries a 10-field source record: source, source type, observation date, retrieval time, geography, transform version, freshness, confidence, limitations, and correction status. A fact without one does not render — the interface refuses.

Freshness thresholds

Prices and stock older than 6 hours render only with a stale flag; older than 7 days they do not render at all.

Recall checking

Products are matched against CPSC recall data by UPC. A recalled product leaves every basket before optimization starts.

How money works here

Commissions never touch match scores, worth-it labels, or basket math — that separation is enforced by automated tests, not policy. Nothing commercial ever sits between you and a required item, a safety warning, or a deadline.

Required list items, safety and recall warnings, dress-code restrictions, corrections, price changes, assistance resources, and deadlines are always available without an account and without a Season Pass.