diff --git a/docs/work-orders/phase-1/README.md b/docs/work-orders/phase-1/README.md
index 449aac5..cc37218 100644
--- a/docs/work-orders/phase-1/README.md
+++ b/docs/work-orders/phase-1/README.md
@@ -157,6 +157,18 @@ Endpoints legados (`GetWorkOrderList`, `GetWorkorderById`, etc.) **não foram al
 
 ---
 
+## Add-On indicator (SH-184)
+
+- Coluna `IsAddOn` persistida; legacy `WorkOrderType.AddOn` (7) backfilled.
+- **Create:** cutoff preview (scheduled) ou hint manual quando unscheduled (`request.IsAddOn`).
+- **Patch schedule** (`scheduledDate`, `targetWeek`, `scheduleWeekOnly`): servidor **recalcula** `IsAddOn` e audita mudanças.
+- **Schedule cleared:** `IsAddOn = false`.
+- Search `Types=AddOn` matches legacy type 7 **or** `IsAddOn`.
+
+Contrato FE: [shoc-frontend-new PR #102](https://github.com/Sea-Haven-Industries/shoc-frontend-new/pull/102).
+
+---
+
 ## Próximo passo
 
 **Fase 2** — Inline edit + concorrência (dual RowVersion, audit por campo, PATCH granular).