# Documenter — F-021 Orders module

## Summary
Orders module records purchase truth with immutable item snapshots, an explicit state machine, and ownership-scoped reads. OrderCreated is emitted on every creation; OrderPaid and OrderCancelled are emitted on those transitions.

## Public API notes

| Route | Access | Result |
|---|---|---|
| POST /orders | authenticated | Creates order with snapshots, returns PENDING |
| POST /orders/:id/transitions | authenticated | Validates and applies state transition |
| GET /orders/:id | authenticated | Returns order with items, scoped to user |

## Errors
- `ORDER_STATE_TRANSITION_INVALID` — HTTP 409
- `ORDER_NOT_FOUND` — HTTP 404

## State machine
PENDING -> AWAITING_PAYMENT or CANCELLED
AWAITING_PAYMENT -> PAID or CANCELLED
PAID -> PROCESSING, SHIPPED, CANCELLED, REFUNDED
PROCESSING -> SHIPPED, CANCELLED, REFUNDED
SHIPPED -> DELIVERED, PARTIALLY_REFUNDED
DELIVERED -> PARTIALLY_REFUNDED
CANCELLED, REFUNDED, PARTIALLY_REFUNDED are terminal.

## Evidence
- `work/artifacts/F-021/architect.md`
- `work/artifacts/F-021/implementer.md`
- `work/artifacts/F-021/reviewer.json`
- `work/artifacts/F-021/security.json`
- `work/artifacts/F-021/qa.json`