diff --git a/src/test-utils/model-auth-mock.ts b/src/test-utils/model-auth-mock.ts
index 8737fd31e6c..92553062273 100644
--- a/src/test-utils/model-auth-mock.ts
+++ b/src/test-utils/model-auth-mock.ts
@@ -1,8 +1,13 @@
 import { vi } from "vitest";
 
-export function createModelAuthMockModule() {
+type ModelAuthMockModule = {
+  resolveApiKeyForProvider: (...args: unknown[]) => unknown;
+  requireApiKey: (auth: { apiKey?: string; mode?: string }, provider: string) => string;
+};
+
+export function createModelAuthMockModule(): ModelAuthMockModule {
   return {
-    resolveApiKeyForProvider: vi.fn(),
+    resolveApiKeyForProvider: vi.fn() as (...args: unknown[]) => unknown,
     requireApiKey: (auth: { apiKey?: string; mode?: string }, provider: string) => {
       if (auth?.apiKey) {
         return auth.apiKey;