diff --git a/metagpt/roles/qa_engineer.py b/metagpt/roles/qa_engineer.py
index de09cc4f0..f2e011ffd 100644
--- a/metagpt/roles/qa_engineer.py
+++ b/metagpt/roles/qa_engineer.py
@@ -169,4 +169,6 @@ class QaEngineer(Role):
         )
 
     async def _observe(self, ignore_memory=False) -> int:
+        # This role has events that trigger and execute themselves based on conditions, and cannot rely on the
+        # content of memory to activate.
         return await super(QaEngineer, self)._observe(ignore_memory=True)