diff --git a/src/agents/model-fallback.run-embedded.e2e.test.ts b/src/agents/model-fallback.run-embedded.e2e.test.ts
index da6111a16d3..2c1fe0284cd 100644
--- a/src/agents/model-fallback.run-embedded.e2e.test.ts
+++ b/src/agents/model-fallback.run-embedded.e2e.test.ts
@@ -328,12 +328,10 @@ function mockPrimaryRunLoopRateLimitThenFallbackSuccess(errorMessage: string) {
 
 function expectOpenAiThenGroqAttemptOrder(params?: { expectOpenAiAuthProfileId?: string }) {
   expect(runEmbeddedAttemptMock).toHaveBeenCalledTimes(2);
-  const firstCall = runEmbeddedAttemptMock.mock.calls.at(0)?.[0] as
+  const firstCall = runEmbeddedAttemptMock.mock.calls[0]?.[0] as
     | { provider?: string; authProfileId?: string }
     | undefined;
-  const secondCall = runEmbeddedAttemptMock.mock.calls.at(1)?.[0] as
-    | { provider?: string }
-    | undefined;
+  const secondCall = runEmbeddedAttemptMock.mock.calls[1]?.[0] as { provider?: string } | undefined;
   if (!firstCall || !secondCall) {
     throw new Error("expected primary and fallback embedded run attempts");
   }
@@ -704,7 +702,7 @@ describe("runWithModelFallback + runEmbeddedPiAgent failover behavior", () => {
       expect((thrown as Error).message).toBe("Operation aborted");
 
       expect(runEmbeddedAttemptMock).toHaveBeenCalledTimes(1);
-      const firstCall = runEmbeddedAttemptMock.mock.calls.at(0)?.[0] as
+      const firstCall = runEmbeddedAttemptMock.mock.calls[0]?.[0] as
         | { provider?: string }
         | undefined;
       expect(firstCall?.provider).toBe("openai");