diff --git a/js/plugins/vertexai/src/evaluation.ts b/js/plugins/vertexai/src/evaluation.ts
index 57d886b01..39aeb6168 100644
--- a/js/plugins/vertexai/src/evaluation.ts
+++ b/js/plugins/vertexai/src/evaluation.ts
@@ -16,7 +16,6 @@
 
 import { Action } from '@genkit-ai/core';
 import { GoogleAuth } from 'google-auth-library';
-import { JSONClient } from 'google-auth-library/build/src/auth/googleauth';
 import z from 'zod';
 import { EvaluatorFactory } from './evaluator_factory';
 
@@ -52,7 +51,7 @@ export type VertexAIEvaluationMetric =
   | VertexAIEvaluationMetricConfig;
 
 export function vertexEvaluators(
-  auth: GoogleAuth<JSONClient>,
+  auth: GoogleAuth,
   metrics: VertexAIEvaluationMetric[],
   projectId: string,
   location: string