diff --git a/backend/src/main/java/org/raddatz/familienarchiv/timeline/TimelineEvent.java b/backend/src/main/java/org/raddatz/familienarchiv/timeline/TimelineEvent.java
index 86155500..e9978022 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/timeline/TimelineEvent.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/timeline/TimelineEvent.java
@@ -99,9 +99,11 @@ public class TimelineEvent {
      * CWE-639 — see ADR-040).
      */
     @Column(name = "created_by", nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID createdBy;
 
     @CreationTimestamp
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private LocalDateTime createdAt;
 
     /**
@@ -112,9 +114,11 @@ public class TimelineEvent {
      * stale. Same forgery rationale as {@link #createdBy}.
      */
     @Column(name = "updated_by", nullable = false)
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private UUID updatedBy;
 
     @UpdateTimestamp
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private LocalDateTime updatedAt;
 
     /**
@@ -125,5 +129,6 @@ public class TimelineEvent {
      * internals (CWE-209).
      */
     @Version
+    @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private Long version;
 }