diff --git a/docs/architecture/c4/l3-backend-3g-supporting.puml b/docs/architecture/c4/l3-backend-3g-supporting.puml
index ed6a370b..8f550f89 100644
--- a/docs/architecture/c4/l3-backend-3g-supporting.puml
+++ b/docs/architecture/c4/l3-backend-3g-supporting.puml
@@ -20,6 +20,7 @@ System_Boundary(backend, "API Backend (Spring Boot)") {
     Component(geschSvc, "GeschichteService", "Spring Service", "Manages story lifecycle (DRAFT → PUBLISHED with timestamp). Supports two subtypes: STORY (prose) and JOURNEY (ordered JourneyItem sequence). Sanitizes HTML body with an allowlist policy.")
     Component(geschQuerySvc, "GeschichteQueryService", "Spring Service", "Read-only facade over GeschichteRepository. Exposes existsById() and findById() to prevent JourneyItemService from crossing domain boundaries.")
     Component(journeyItemSvc, "JourneyItemService", "Spring Service", "Manages journey item lifecycle: append (100-item cap), updateNote (three-way PATCH), delete, and reorder (DEFERRABLE position swap). Serves both STORY and JOURNEY subtypes.")
+    Component(journeyListener, "JourneyItemDocumentDeleteListener", "Spring @EventListener", "Consumes DocumentDeletingEvent synchronously inside the delete transaction and removes note-less journey items before ON DELETE SET NULL fires, preventing a chk_journey_item_not_empty violation. See ADR-038.")
     Component(exHandler, "GlobalExceptionHandler", "Spring @RestControllerAdvice", "Converts DomainException, validation errors, and generic exceptions to ErrorResponse JSON with machine-readable ErrorCode and HTTP status.")
 }
 
@@ -44,6 +45,8 @@ Rel(geschCtrl, journeyItemSvc, "Delegates journey item CRUD")
 Rel(journeyItemSvc, geschQuerySvc, "Checks Geschichte existence")
 Rel(geschQuerySvc, db, "Reads geschichten", "JDBC")
 Rel(journeyItemSvc, db, "Reads / writes journey_items", "JDBC")
+Rel(documentSvc, journeyListener, "DocumentDeletingEvent", "in-process event")
+Rel(journeyListener, db, "Deletes note-less journey_items", "JDBC")
 Rel(auditSvc, db, "Writes audit_log", "JDBC")
 Rel(auditQuery, db, "Reads audit_log", "JDBC")
 Rel(notifSvc, db, "Reads / writes notifications", "JDBC")