diff --git a/packages/catalog-model/src/model/jsonSchema/zod.ts b/packages/catalog-model/src/model/jsonSchema/zod.ts
index ea82263cac..61135f1b04 100644
--- a/packages/catalog-model/src/model/jsonSchema/zod.ts
+++ b/packages/catalog-model/src/model/jsonSchema/zod.ts
@@ -25,13 +25,16 @@ export const jsonObjectSchema = z
     message: 'Invalid JSON schema',
   });
 
-export const jsonSchemaSchema = z.record(z.string(), z.unknown()).refine(
-  (x): x is JsonObject => {
+export const jsonSchemaSchema = z
+  .record(z.string(), z.unknown())
+  .superRefine((x, ctx): x is JsonObject => {
     try {
       return validateMetaSchema(x);
-    } catch {
+    } catch (error) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: error instanceof Error ? error.message : 'Invalid JSON schema',
+      });
       return false;
     }
-  },
-  { message: 'Invalid JSON schema' },
-);
+  });
diff --git a/packages/catalog-model/src/model/sources/CatalogModelSources.ts b/packages/catalog-model/src/model/sources/CatalogModelSources.ts
index 6c021be5e4..114e4ae376 100644
--- a/packages/catalog-model/src/model/sources/CatalogModelSources.ts
+++ b/packages/catalog-model/src/model/sources/CatalogModelSources.ts
@@ -19,6 +19,7 @@ import { defaultCatalogEntityModel } from '../defaultCatalogEntityModel';
 import { StaticCatalogModelSource } from './StaticCatalogModelSource';
 import { CatalogModelSource } from './types';
 import { CatalogModelLayer } from '../types';
+import uniqBy from 'lodash/uniqBy';
 
 /**
  * A helper for creating common catalog model sources.
@@ -35,24 +36,13 @@ export class CatalogModelSources {
 
   /**
    * Provides a static catalog model on top of the default one (which is
-   * included automatically).
+   * included automatically). User-provided layers take precedence over the
+   * default model when layer IDs overlap.
    */
   static static(layers: CatalogModelLayer[]): CatalogModelSource {
-    const allLayers = [...layers, defaultCatalogEntityModel];
-    const seen = new Set<string>();
-    const deduped: CatalogModelLayer[] = [];
-    for (const layer of allLayers) {
-      if (seen.has(layer.layerId)) {
-        // eslint-disable-next-line no-console
-        console.warn(
-          `Duplicate catalog model layer ID "${layer.layerId}" detected; only the first occurrence will be used`,
-        );
-      } else {
-        seen.add(layer.layerId);
-        deduped.push(layer);
-      }
-    }
-    return new StaticCatalogModelSource(deduped);
+    return new StaticCatalogModelSource(
+      uniqBy([...layers, defaultCatalogEntityModel], 'layerId'),
+    );
   }
 
   private constructor() {
diff --git a/plugins/catalog-backend/src/model/ModelHolder.ts b/plugins/catalog-backend/src/model/ModelHolder.ts
index 146ef59f85..96b2de46dc 100644
--- a/plugins/catalog-backend/src/model/ModelHolder.ts
+++ b/plugins/catalog-backend/src/model/ModelHolder.ts
@@ -68,7 +68,7 @@ export class ModelHolder {
             }
             return ls;
           } finally {
-            await iter.return(undefined as void);
+            await iter.return(undefined);
           }
         }),
       );