diff --git a/extensions/browser/src/browser/control-auth.auto-token.test.ts b/extensions/browser/src/browser/control-auth.auto-token.test.ts
index b2da74c3228..fe978ee1a44 100644
--- a/extensions/browser/src/browser/control-auth.auto-token.test.ts
+++ b/extensions/browser/src/browser/control-auth.auto-token.test.ts
@@ -64,7 +64,11 @@ vi.mock("../gateway/auth.js", () => ({
 }));
 
 function readPersistedConfig(): OpenClawConfig {
-  const persistedCfg = mocks.writeConfigFile.mock.calls[0]?.[0];
+  const [call] = mocks.writeConfigFile.mock.calls;
+  if (!call) {
+    throw new Error("expected persisted config write");
+  }
+  const [persistedCfg] = call;
   if (!persistedCfg) {
     throw new Error("expected persisted config");
   }