# Documenter — F-017 Pricing module

## Summary
Documented F-017 pricing behavior in this evidence artifact. Project README updates are not applied during document stage because the active repository guard restricts `project/` product edits to build/implementer state.

## Public API notes

Pricing owns server-side price and VAT truth for product variants. Callers provide variant identity and quantity only; client-supplied prices, tax amounts, discounts, subtotals, or totals are not trusted.

| Route                             | Access     | Result                                      |
| --------------------------------- | ---------- | ------------------------------------------- |
| GET /pricing/variants/:variantId  | public     | `200` current server-side variant price     |
| PUT /pricing/variants/:variantId  | admin only | `200` updated price and history row written |
| POST /pricing/calculate           | public     | `200` calculated net subtotal, VAT and total |

## Error codes
- `PRICING_PRICE_NOT_FOUND` — HTTP 404
- `INVALID_PRICE` — HTTP 422

## Money and VAT rules
- Money is represented as integer cents only.
- Currency is fixed to `EUR`.
- Stored price is `netUnitAmountCents` before VAT.
- VAT rates:
  - `general` = 21% (`2100` basis points)
  - `reduced` = 10% (`1000` basis points)
- Calculation: `netSubtotal = netUnitAmountCents * quantity`; `vatAmount = round(netSubtotal * vatBps / 10000)`; `total = netSubtotal + vatAmount`.

## Audit/history
- Current price lives in `pricing_variant_prices`.
- Every create/update writes an append-only row to `pricing_price_history` with previous and new values.
- Variant ids are opaque UUIDs; pricing does not import catalog internals or join catalog tables.

## Evidence
- `work/artifacts/F-017/architect.md`
- `work/artifacts/F-017/implementer.md`
- `work/artifacts/F-017/reviewer.json`
- `work/artifacts/F-017/security.json`
- `work/artifacts/F-017/qa.json`
