# 0007. Who is authoritative

- Status: Accepted
- Date: 2026-10-27

## Context

When several devices and a hub compute totals, they could disagree, through bugs, stale catalog data or tampering.

## Decision

In single-device mode, the device is authoritative. With a hub, the hub recomputes order totals using the same `packages/core` library, and its result wins; devices re-render with the hub's totals.

## Consequences

- There is one rule set everywhere, because devices and the server share `core`.
- Devices still compute totals locally so they keep working offline; the hub corrects them when they sync.