diff --git a/lib/galaxy/tool_util/verify/__init__.py b/lib/galaxy/tool_util/verify/__init__.py
index d1dad596d0a0..6ddfefeb69f8 100644
--- a/lib/galaxy/tool_util/verify/__init__.py
+++ b/lib/galaxy/tool_util/verify/__init__.py
@@ -653,7 +653,7 @@ def verify_file_contents_against_dict(
         output_value = json.loads(output_content.decode("utf-8"))
         if test_properties != output_value:
             template = "Output [%s] value [%s] does not match expected value [%s]."
-            message = template % (output_id, output_value, test_properties)
+            message = template % (item_label, output_value, test_properties)
             raise AssertionError(message)