catalog / commerce

Shopping Cart

Hold items, keep the total honest, and survive the customer leaving and coming back.

18 capabilities 2 sections reference specification

Build against it

# give your agent the catalog — no account, no install
claude mcp add provespec -- npx -y provespec-mcp

# then, from any agent session
spec_get(slug: "shopping-cart")                → the capability tree
spec_checklist(slug: "shopping-cart")          → the questions to answer
spec_grade(slug: "shopping-cart", grades: [...])  → parity % + the gap list

# or just fetch it
curl https://provespec.com/catalog/shopping-cart/spec.json

Grade every capability below as yes · partial · no · na, with a file reference as evidence. Whatever you leave ungraded counts as missing — the gap list is the work queue.

Or just paste this to your agent

Use the ProveSpec MCP server. Fetch the "shopping-cart" spec with
spec_get, then walk spec_checklist and grade this repository against it —
one verdict per capability, each with a file reference as the note.
Call spec_grade with the results and give me the gap list as the plan.

If the server is not registered, add it first:
  claude mcp add provespec -- npx -y provespec-mcp

The specification

AI 14

Items

✓ Add, update quantity, remove
✓ Variant selection kept distinct size, colour same product, different line
✓ Merge duplicate lines rather than repeat them

Pricing

✓ Line subtotal, cart subtotal, grand total recomputed, never stored stale
✓ Tax calculated by destination and product class
✓ Shipping estimate before checkout
✓ Currency and rounding rules stated no floating-point money

Promotions

✓ Coupon codes with eligibility rules
✓ Stacking policy defined which discounts combine, which do not

Stock

✓ Availability checked at add and again at checkout stock can change in between
✓ Reservation window or explicit lack of one

Persistence

✓ Cart survives reload and session end
✓ Guest cart merges into the account on sign-in the classic lost-cart bug
✓ Abandoned cart retrievable

UI 4

Display

✓ Line items with image, variant, unit and line price
✓ Totals broken down, not just a final number

Feedback

✓ Quantity change updates totals without a full reload
✓ Out-of-stock and price changes surfaced clearly

Download spec.json All 85 specs