# Autonomous Haulage System (AHS) revision history

Append-only Arc G field-change log. Forward-only honesty: events accrue from Arc G adoption.

Model: [Autonomous Haulage System (AHS)](/models/hitachi-ahs.md)

_No events on file. Arc G is forward-only; the recorded event log accrues from Arc G adoption (2026-06-04) and records material changes as they flow through the updateEntityField chokepoint. For the current state of this model, see the model page._

## Forward-only note

Arc G is forward-only. The event log accrues from the Arc G adoption point. Fields with no events post-baseline equal the current cached value and are not independently verified at any prior date. To restate a recorded change, write a new event through the updateEntityField chokepoint.

_Canonical URL: /models/hitachi-ahs/history. REST: /v1/models/9e12941f-24f6-4ffe-b913-9f628ef1147f/history. HTML: [/models/hitachi-ahs/history](/models/hitachi-ahs/history)._