diff --git a/src/gateway/env-deprecation.test.ts b/src/gateway/env-deprecation.test.ts
index c04bbad1af5..63afb7c40af 100644
--- a/src/gateway/env-deprecation.test.ts
+++ b/src/gateway/env-deprecation.test.ts
@@ -31,7 +31,7 @@ describe("warnLegacyOpenClawEnvVars", () => {
     });
 
     expect(emitWarning).toHaveBeenCalledOnce();
-    const [message, options] = emitWarning.mock.calls[0] as [
+    const [message, options] = emitWarning.mock.calls.at(0) as [
       string,
       { code: string; type: string },
     ];
diff --git a/src/gateway/http-endpoint-helpers.test.ts b/src/gateway/http-endpoint-helpers.test.ts
index 36d7c6b7ecf..cb66b1df7a6 100644
--- a/src/gateway/http-endpoint-helpers.test.ts
+++ b/src/gateway/http-endpoint-helpers.test.ts
@@ -157,7 +157,7 @@ describe("handleGatewayPostJsonEndpoint", () => {
       },
     );
 
-    const [, requestAuth] = (resolveOperatorScopes.mock.calls[0] as unknown as
+    const [, requestAuth] = (resolveOperatorScopes.mock.calls.at(0) as unknown as
       | [IncomingMessage, { authMethod?: string; trustDeclaredOperatorScopes: boolean }]
       | undefined) ?? [undefined, undefined];
     expect(requestAuth?.authMethod).toBe("token");
diff --git a/src/gateway/mcp-http.test.ts b/src/gateway/mcp-http.test.ts
index f79545298b5..ff758c64d8e 100644
--- a/src/gateway/mcp-http.test.ts
+++ b/src/gateway/mcp-http.test.ts
@@ -519,7 +519,7 @@ describe("mcp loopback server", () => {
     expect(response.status).toBe(200);
     expect(payload.result?.isError).toBe(false);
     expect(execute).toHaveBeenCalledTimes(1);
-    const [callId, params, signal] = execute.mock.calls[0] ?? [];
+    const [callId, params, signal] = execute.mock.calls.at(0) ?? [];
     expect(callId).toMatch(/^mcp-/);
     expect(params).toEqual({ body: "hello" });
     expect(signal).toBeInstanceOf(AbortSignal);
diff --git a/src/gateway/server-methods/cron.validation.test.ts b/src/gateway/server-methods/cron.validation.test.ts
index a4f83c43097..5443e5284d0 100644
--- a/src/gateway/server-methods/cron.validation.test.ts
+++ b/src/gateway/server-methods/cron.validation.test.ts
@@ -183,7 +183,7 @@ function expectResponseError(
   respond: ReturnType<typeof vi.fn>,
   expected: { code?: string; messageIncludes?: string },
 ) {
-  const call = respond.mock.calls[0];
+  const call = respond.mock.calls.at(0);
   if (!call) {
     throw new Error("expected response call");
   }
diff --git a/src/gateway/server-methods/devices.test.ts b/src/gateway/server-methods/devices.test.ts
index fae9405a8e8..b8c929d3d67 100644
--- a/src/gateway/server-methods/devices.test.ts
+++ b/src/gateway/server-methods/devices.test.ts
@@ -113,7 +113,7 @@ function mockRotateOperatorTokenSuccess(): void {
 function expectRespondedErrorMessage(opts: GatewayRequestHandlerOptions, message: string): void {
   const respond = opts.respond as ReturnType<typeof vi.fn>;
   expect(respond).toHaveBeenCalledTimes(1);
-  const call = respond.mock.calls[0] as unknown as [boolean, unknown, { message?: string }];
+  const call = respond.mock.calls.at(0) as unknown as [boolean, unknown, { message?: string }];
   expect(call[0]).toBe(false);
   expect(call[1]).toBeUndefined();
   expect(call[2]?.message).toBe(message);
diff --git a/src/gateway/server-methods/environments.test.ts b/src/gateway/server-methods/environments.test.ts
index 04c7af49619..f66c93f91b4 100644
--- a/src/gateway/server-methods/environments.test.ts
+++ b/src/gateway/server-methods/environments.test.ts
@@ -40,7 +40,11 @@ async function callEnvironmentMethod(
     respond,
     context: mockContext(),
   } as never);
-  return respond.mock.calls[0];
+  const call = respond.mock.calls.at(0);
+  if (call === undefined) {
+    throw new Error("expected environments handler to respond");
+  }
+  return call;
 }
 
 beforeEach(() => {
diff --git a/src/gateway/server-methods/models.test.ts b/src/gateway/server-methods/models.test.ts
index 7e0adfedf96..aa95bffc01d 100644
--- a/src/gateway/server-methods/models.test.ts
+++ b/src/gateway/server-methods/models.test.ts
@@ -236,7 +236,7 @@ describe("models.list", () => {
       } as never,
     });
 
-    const call = respond.mock.calls[0] as
+    const call = respond.mock.calls.at(0) as
       | [boolean, unknown, { code?: number; message?: string }]
       | undefined;
     expect(call?.[0]).toBe(false);
diff --git a/src/gateway/server-methods/native-hook-relay.test.ts b/src/gateway/server-methods/native-hook-relay.test.ts
index a4cc03917de..a546882dec5 100644
--- a/src/gateway/server-methods/native-hook-relay.test.ts
+++ b/src/gateway/server-methods/native-hook-relay.test.ts
@@ -55,7 +55,7 @@ describe("native hook relay gateway method", () => {
       context: {} as never,
     });
 
-    const call = respond.mock.calls[0] as
+    const call = respond.mock.calls.at(0) as
       | [boolean, unknown, { code?: string; message?: string }]
       | undefined;
     expect(call?.[0]).toBe(false);
diff --git a/src/gateway/server-methods/secrets.test.ts b/src/gateway/server-methods/secrets.test.ts
index 91256527786..6b5cd983703 100644
--- a/src/gateway/server-methods/secrets.test.ts
+++ b/src/gateway/server-methods/secrets.test.ts
@@ -53,7 +53,7 @@ function expectRespondError(
   respond: ReturnType<typeof vi.fn>,
   expected: { code: string; message?: string },
 ): void {
-  const call = respond.mock.calls[0];
+  const call = respond.mock.calls.at(0);
   expect(call?.[0]).toBe(false);
   expect(call?.[1]).toBeUndefined();
   const error = requireRecord(call?.[2]);
diff --git a/src/gateway/server-methods/send.test.ts b/src/gateway/server-methods/send.test.ts
index 3045e0aae15..6ef666bf769 100644
--- a/src/gateway/server-methods/send.test.ts
+++ b/src/gateway/server-methods/send.test.ts
@@ -1014,7 +1014,7 @@ describe("gateway send mirroring", () => {
       idempotencyKey: "idem-send-options",
     });
 
-    const options = mocks.deliverOutboundPayloads.mock.calls[0]?.[0];
+    const options = mocks.deliverOutboundPayloads.mock.calls.at(0)?.[0];
     expect(options?.forceDocument).toBe(true);
     expect(options?.silent).toBe(true);
     expect(options?.formatting).toEqual({ parseMode: "HTML" });
diff --git a/src/gateway/server-methods/sessions.send-followup-status.test.ts b/src/gateway/server-methods/sessions.send-followup-status.test.ts
index e098118b8d1..61fda04d964 100644
--- a/src/gateway/server-methods/sessions.send-followup-status.test.ts
+++ b/src/gateway/server-methods/sessions.send-followup-status.test.ts
@@ -110,7 +110,7 @@ describe("sessions.send completed subagent follow-up status", () => {
       isWebchatConnect: () => false,
     });
 
-    const call = respondMock.mock.calls[0] as
+    const call = respondMock.mock.calls.at(0) as
       | [boolean, { runId?: string; status?: string; messageSeq?: number }, unknown?, unknown?]
       | undefined;
     expect(call?.[0]).toBe(true);
diff --git a/src/gateway/server-methods/skills-upload.test.ts b/src/gateway/server-methods/skills-upload.test.ts
index 07b57ac23c7..e2f77b9b277 100644
--- a/src/gateway/server-methods/skills-upload.test.ts
+++ b/src/gateway/server-methods/skills-upload.test.ts
@@ -141,7 +141,7 @@ function expectError(result: CallResult, code: string, message: string): void {
 }
 
 function firstCallArg<T>(mock: { mock: { calls: unknown[][] } }, _type?: (value: T) => T): T {
-  const call = mock.mock.calls[0];
+  const call = mock.mock.calls.at(0);
   if (!call) {
     throw new Error("Expected first mock call");
   }
diff --git a/src/gateway/server-methods/tts.test.ts b/src/gateway/server-methods/tts.test.ts
index 5186f278a50..3b79b53f4d5 100644
--- a/src/gateway/server-methods/tts.test.ts
+++ b/src/gateway/server-methods/tts.test.ts
@@ -76,7 +76,7 @@ describe("ttsHandlers", () => {
       context: { getRuntimeConfig: mocks.getRuntimeConfig },
     } as never);
 
-    const call = respond.mock.calls[0] as
+    const call = respond.mock.calls.at(0) as
       | [boolean, unknown, { code?: number; message?: string }]
       | undefined;
     expect(call?.[0]).toBe(false);
diff --git a/src/gateway/server-methods/usage.test.ts b/src/gateway/server-methods/usage.test.ts
index 8a9e9e6996c..d9b41a48ab0 100644
--- a/src/gateway/server-methods/usage.test.ts
+++ b/src/gateway/server-methods/usage.test.ts
@@ -157,7 +157,7 @@ describe("gateway usage helpers", () => {
     expect(a.totals.totalTokens).toBe(1);
     expect(b.totals.totalTokens).toBe(1);
     expect(vi.mocked(loadCostUsageSummaryFromCache)).toHaveBeenCalledTimes(1);
-    expect(vi.mocked(loadCostUsageSummaryFromCache).mock.calls[0]?.[0]?.refreshMode).toBe(
+    expect(vi.mocked(loadCostUsageSummaryFromCache).mock.calls.at(0)?.[0]?.refreshMode).toBe(
       "sync-when-empty",
     );
   });