diff --git a/packages/core/src/scheduler/policy.test.ts b/packages/core/src/scheduler/policy.test.ts
index 34491f788c..4f8e48ae54 100644
--- a/packages/core/src/scheduler/policy.test.ts
+++ b/packages/core/src/scheduler/policy.test.ts
@@ -770,7 +770,7 @@ describe('policy.ts', () => {
         expect.objectContaining({
           toolName: 'write_file',
           argsPattern:
-            '\\\\0' + escapeRegex('"file_path":"src/foo.ts"') + '\\\\0',
+            '\\x00' + escapeRegex('"file_path":"src/foo.ts"') + '\\x00',
         }),
       );
     });