diff --git a/src/tools/monaco/validate.ts b/src/tools/monaco/validate.ts
index d08d6c8..e3c15a2 100644
--- a/src/tools/monaco/validate.ts
+++ b/src/tools/monaco/validate.ts
@@ -26,15 +26,17 @@ export function validateDSL(monaco: typeof MonacoEditor, dsl: string): Marker[]
       }
 
       const extraInformation: Marker["extraInformation"] = {};
-      const errorMetadata = singleErr.metadata as any;
-      if (errorMetadata.errorType) {
-        extraInformation.error = errorMetadata.errorType;
-      }
-      ["typeName", "relation"].forEach((field) => {
-        if (errorMetadata[field]) {
-          (extraInformation as any)[field] = errorMetadata[field];
+      const errorMetadata = singleErr.metadata;
+      if (errorMetadata) {
+        if ("errorType" in errorMetadata) {
+          extraInformation.error = errorMetadata.errorType;
         }
-      });
+        ["typeName", "relation"].forEach((field) => {
+          if (field in errorMetadata) {
+            (extraInformation as any)[field] = (errorMetadata as any)[field];
+          }
+        });
+      }
 
       markers.push({
         message: singleErr.msg,