diff --git a/metagpt/software_company.py b/metagpt/software_company.py
index 4bedec0e1..d29d8926d 100644
--- a/metagpt/software_company.py
+++ b/metagpt/software_company.py
@@ -4,9 +4,10 @@
 @Time    : 2023/5/12 00:30
 @Author  : alexanderwu
 @File    : software_company.py
-@Modified By: mashenquan, 2023-11-1. Optimization:
-    1. Standardize the design of message filtering-related features.
-    2. Abandon the design of having `Environment` store all messages.
+@Modified By: mashenquan, 2023-11-1. According to Chapter 2.2.1 and 2.2.2 of RFC 116:
+        1. Change the data type of the `cause_by` value in the `Message` to a string to support the new message
+            distribution feature.
+        2. Abandon the design of having `Environment` store all messages.
 """
 from pydantic import BaseModel, Field