diff --git a/tests/cpydiff/core_arguments.py b/tests/cpydiff/core_arguments.py
index a0831ab40c02837d1c34a91a90edbc4e7f7e1ace..4734a806279e22097318255075d31fd7ece2ada3 100644
--- a/tests/cpydiff/core_arguments.py
+++ b/tests/cpydiff/core_arguments.py
@@ -1,8 +1,8 @@
 """
 categories: Core
-description: Error messages may display incorrect argument counts
-cause: Unknown
-workaround: Unknown
+description: Error messages for methods may display unexpected argument counts
+cause: MicroPython counts "self" as an argument.
+workaround: Interpret error messages with the information above in mind.
 """
 try:
     [].append()