diff --git a/tests/test_full_stack_contract.py b/tests/test_full_stack_contract.py
index b0eb04b..3cbba72 100644
--- a/tests/test_full_stack_contract.py
+++ b/tests/test_full_stack_contract.py
@@ -45,6 +45,7 @@ def test_full_stack_product_contract():
     assert "data-testid=\"agent-app\"" in frontend
     assert "data-testid=\"agent-submit\"" in frontend
     assert "data-testid=\"agent-result\"" in frontend
+    assert "data-state={resultState}" in frontend
     assert "data-testid=\"agent-download\"" in frontend
     assert "unwrapInvokeResponse" in frontend_client, "unwrap the /invoke result envelope before rendering"