diff --git a/js/ai/tests/model/middleware_test.ts b/js/ai/tests/model/middleware_test.ts
index ab1c9664da..cebb68eb59 100644
--- a/js/ai/tests/model/middleware_test.ts
+++ b/js/ai/tests/model/middleware_test.ts
@@ -18,16 +18,16 @@ import assert from 'node:assert';
 import { beforeEach, describe, it } from 'node:test';
 import { DocumentData } from '../../src/document.js';
 import {
-  defineModel,
   GenerateRequest,
   GenerateResponseData,
   MessageData,
   Part,
+  defineModel,
 } from '../../src/model.js';
 import {
-  augmentWithContext,
   AugmentWithContextOptions,
   CONTEXT_PREFACE,
+  augmentWithContext,
   simulateSystemPrompt,
   validateSupport,
 } from '../../src/model/middleware.js';
diff --git a/js/plugins/vertexai/src/index.ts b/js/plugins/vertexai/src/index.ts
index 48964bdb5d..1cf3889d55 100644
--- a/js/plugins/vertexai/src/index.ts
+++ b/js/plugins/vertexai/src/index.ts
@@ -90,13 +90,18 @@ export interface PluginOptions {
   modelGardenModels?: ModelReference<any>[];
 }
 
+const CLOUD_PLATFROM_OAUTH_SCOPE =
+  'https://www.googleapis.com/auth/cloud-platform';
+
 /**
  * Add Google Cloud Vertex AI to Genkit. Includes Gemini and Imagen models and text embedder.
  */
 export const vertexAI: Plugin<[PluginOptions] | []> = genkitPlugin(
   'vertexai',
   async (options?: PluginOptions) => {
-    const authClient = new GoogleAuth(options?.googleAuth);
+    const authClient = new GoogleAuth(
+      options?.googleAuth ?? { scopes: [CLOUD_PLATFROM_OAUTH_SCOPE] }
+    );
     const projectId = options?.projectId || (await authClient.getProjectId());
     const location = options?.location || 'us-central1';