diff --git a/Assets/Scripts/Editor/GON/StageEditor/StageInspectorPanel.cs b/Assets/Scripts/Editor/GON/StageEditor/StageInspectorPanel.cs
index 5a41b1b..04de5b9 100644
--- a/Assets/Scripts/Editor/GON/StageEditor/StageInspectorPanel.cs
+++ b/Assets/Scripts/Editor/GON/StageEditor/StageInspectorPanel.cs
@@ -138,6 +138,45 @@ namespace Editor.GON.StageEditor
 
             Add(new HelpBox("The grid is infinite/sparse. The stage size emerges from painted cells and logical objects.", HelpBoxMessageType.Info));
             Add(new HelpBox("Editor plane uses X/Y. Later, the stage baker can map editor Y to Unity Z and floor index to Unity Y.", HelpBoxMessageType.Info));
+            BuildWorldSyncInspector();
+        }
+
+        private void BuildWorldSyncInspector()
+        {
+            var spacer = new VisualElement
+            {
+                style =
+                {
+                    height = 10
+                }
+            };
+            Add(spacer);
+
+            var section = new Label("World Sync")
+            {
+                style =
+                {
+                    unityFontStyleAndWeight = FontStyle.Bold
+                }
+            };
+            Add(section);
+
+            var sync = stage.worldSync;
+            if (sync is null || !sync.HasSync)
+            {
+                Add(new HelpBox("Not synced.", HelpBoxMessageType.Info));
+                return;
+            }
+
+            sync.EnsureDefaults();
+            AddReadOnlyLine("World Stage", string.IsNullOrEmpty(sync.worldStageDisplayName)
+                ? sync.worldStageId
+                : sync.worldStageDisplayName);
+            AddReadOnlyLine("Stage Id", sync.worldStageId);
+            AddReadOnlyLine("Kind", sync.worldStageKind.ToString());
+            AddReadOnlyLine("Layer", sync.worldLayer.ToString());
+            AddReadOnlyLine("Synced At", string.IsNullOrEmpty(sync.syncedAt) ? "-" : sync.syncedAt);
+            AddReadOnlyLine("Hash", ShortHash(sync.contractHash));
         }
 
         private void BuildObjectInspector(StageObjectDefinition obj)
@@ -313,5 +352,15 @@ namespace Editor.GON.StageEditor
 
             Add(row);
         }
+
+        private static string ShortHash(string hash)
+        {
+            if (string.IsNullOrEmpty(hash))
+            {
+                return "-";
+            }
+
+            return hash.Length <= 12 ? hash : hash[..12];
+        }
     }
 }
diff --git a/Assets/Scripts/Editor/GON/WorldEditor/WorldLayoutValidator.cs b/Assets/Scripts/Editor/GON/WorldEditor/WorldLayoutValidator.cs
index 10d8fba..50fdae4 100644
--- a/Assets/Scripts/Editor/GON/WorldEditor/WorldLayoutValidator.cs
+++ b/Assets/Scripts/Editor/GON/WorldEditor/WorldLayoutValidator.cs
@@ -51,6 +51,8 @@ namespace Editor.GON.WorldEditor
                 }
 
                 stage.EnsureDefaults();
+                ValidateStageDefinitionSync(layout, stage, messages);
+
                 var endpointCount = 0;
                 foreach (var endpoint in layout.endpoints)
                 {
@@ -88,6 +90,46 @@ namespace Editor.GON.WorldEditor
             }
         }
 
+        private static void ValidateStageDefinitionSync(
+            WorldLayoutSO layout,
+            WorldStageAuthoring stage,
+            List<WorldValidationMessage> messages)
+        {
+            if (stage.stageDefinition is null)
+            {
+                messages.Add(new WorldValidationMessage(WorldValidationSeverity.Warning,
+                    "Stage has no StageDefinition. Use Create StageDefinition from the stage inspector.",
+                    stage.id));
+                return;
+            }
+
+            stage.stageDefinition.EnsureDefaults();
+            var sync = stage.stageDefinition.worldSync;
+            if (sync is null || !sync.HasSync)
+            {
+                messages.Add(new WorldValidationMessage(WorldValidationSeverity.Warning,
+                    "StageDefinition is not synced. Use Sync StageDefinition from the stage inspector.",
+                    stage.id));
+                return;
+            }
+
+            if (!string.IsNullOrEmpty(sync.worldStageId) && sync.worldStageId != stage.id)
+            {
+                messages.Add(new WorldValidationMessage(WorldValidationSeverity.Error,
+                    "StageDefinition is synced to another world stage id. Reassign or recreate the StageDefinition.",
+                    stage.id));
+                return;
+            }
+
+            var expectedHash = StageDefinitionSyncer.ComputeExpectedContractHash(layout, stage);
+            if (sync.contractHash != expectedHash)
+            {
+                messages.Add(new WorldValidationMessage(WorldValidationSeverity.Warning,
+                    "StageDefinition sync contract is outdated. Use Sync StageDefinition from the stage inspector.",
+                    stage.id));
+            }
+        }
+
         private static void ValidateEndpoints(WorldLayoutSO layout, List<WorldValidationMessage> messages)
         {
             var nonSocketByTile = new Dictionary<string, JEndpointKind>();