ColorBreak

ColorBreak is a mobile-first decision tool for Magic: The Gathering color breaks. Buyers can judge a live-auction bid in seconds; sellers can price a break against actual marketplace fees, product cost, and fulfillment.

Run locally

npm install
npm run dev

Production validation:

npm run check

npm run build creates dist/, including the committed static data needed by GitHub Pages.

Product model

• A break may contain multiple sealed products from multiple sets.
• Cards go to W/U/B/R/G/M/C/L by the printed color of the front face; lands always go to L.
• Market EV counts every exactly priced card. Sellable EV applies the user’s price threshold. Known EV is the priced lower bound when source data is incomplete.
• verified, estimated, and incomplete are behavioral states. An incomplete result never produces a buyer verdict.
• Seller fees are assessed per purchase. Packing and seller-covered shipping are assessed per shipment. Buyer-paid shipping is not seller revenue.

Data

• data/sealed/*.json: normalized MTGJSON sealed products and collation.
• data/corrections.json: narrowly scoped, sourced product corrections. This layer is authoritative over upstream sealed metadata.
• data/prices/*.json: a compact, timestamped Scryfall bulk-data snapshot containing only exact printings referenced by the normalized corpus. It is refreshed for every deployment and by the daily Pages workflow.
• Scryfall live lookup: globally throttled recovery path for a printing absent from the snapshot; it is not the primary page-load path.
• tcgcsv: best-effort sealed market cost. The seller can always enter actual cost.

Unresolved contents and exact-finish prices are surfaced as named omissions; they are never silently replaced with a proxy. Price-source availability is reported separately from product-content completeness, so a transient remote failure cannot make an otherwise exact product look structurally incomplete.

Structure

• src/domain/: pure valuation, marketplace, and legacy-link contracts.
• src/data/: source adapters and orchestration.
• src/App.tsx: buyer/seller task flows.
• tools/: offline data builders and validators.
• CONTEXT.md: domain language and product intent.
• SPEC.md: current acceptance contract.

The app is a Vite static build and requires no backend or account.