diff --git a/tests/test_o3_pro_output_text_fix.py b/tests/test_o3_pro_output_text_fix.py
index 13ae967..b0706fb 100644
--- a/tests/test_o3_pro_output_text_fix.py
+++ b/tests/test_o3_pro_output_text_fix.py
@@ -34,6 +34,11 @@ class TestO3ProOutputTextFix:
 
     def setup_method(self):
         """Set up the test by ensuring clean registry state."""
+        # Clear the restriction service singleton to ensure clean state
+        import utils.model_restrictions
+
+        utils.model_restrictions._restriction_service = None
+
         # Use the new public API for registry cleanup
         ModelProviderRegistry.reset_for_testing()
         # Provider registration is now handled by inject_transport helper