diff --git a/docs/plans/2026-05-19-notification-outbox-implementation.md b/docs/plans/2026-05-19-notification-outbox-implementation.md
index 7518633..ffc18af 100644
--- a/docs/plans/2026-05-19-notification-outbox-implementation.md
+++ b/docs/plans/2026-05-19-notification-outbox-implementation.md
@@ -705,6 +705,10 @@ public interface INotificationDeliveryAdapter
 
 ---
 
+## Follow-ups (post-merge, not blocking)
+
+- **Share the SMTP helpers (from Task 12 review).** `EmailNotificationDeliveryAdapter` reimplements `ClassifySmtpError`/`SmtpErrorClass`, `ValidateAddresses`, and a `ScrubCredentials` helper because the originals are `internal` to `ScadaLink.NotificationService`. To avoid divergence (especially in the security-relevant credential redaction and the SMTP 4xx/5xx classification policy), promote `CredentialRedactor` to `public`, extract a `public static SmtpErrorClassifier`, and make `ValidateAddresses` shared — then have the adapter call them and delete the duplicates. The project reference already exists, so this is low-cost.
+
 ## Done
 
 The Notification Outbox feature is implemented end to end: site scripts enqueue notifications that store-and-forward to central, the `NotificationOutboxActor` singleton ingests them into the `Notifications` table and delivers them via the Email adapter with retry/parking, operators see KPIs and manage notifications from the Central UI, and the full test suite passes. Teams and other delivery adapters can be added later by implementing `INotificationDeliveryAdapter` and registering it — no other change required.