diff --git a/metagpt/actions/write_code.py b/metagpt/actions/write_code.py
index f2a4744d9..be8690314 100644
--- a/metagpt/actions/write_code.py
+++ b/metagpt/actions/write_code.py
@@ -4,8 +4,8 @@
 @Time    : 2023/5/11 17:45
 @Author  : alexanderwu
 @File    : write_code.py
-@Modified By: mashenquan, 2023-11-1. According to Chapter 2.2.1 and 2.2.2 of RFC 116, change the data type of
-        the `cause_by` value in the `Message` to a string to support the new message distribution feature.
+@Modified By: mashenquan, 2023-11-1. In accordance with Chapter 2.1.3 of RFC 116, modify the data type of the `cause_by`
+            value of the `Message` object.
 """
 from tenacity import retry, stop_after_attempt, wait_fixed
 
@@ -14,7 +14,7 @@ from metagpt.actions.action import Action
 from metagpt.const import WORKSPACE_ROOT
 from metagpt.logs import logger
 from metagpt.schema import Message
-from metagpt.utils.common import CodeParser
+from metagpt.utils.common import CodeParser, get_class_name
 
 PROMPT_TEMPLATE = """
 NOTICE
@@ -58,8 +58,7 @@ class WriteCode(Action):
         if self._is_invalid(filename):
             return
 
-        message_filter = {WriteDesign}
-        design = [i for i in context if i.contain_any(message_filter)][0]
+        design = [i for i in context if i.cause_by == get_class_name(WriteDesign)][0]
 
         ws_name = CodeParser.parse_str(block="Python package name", text=design.content)
         ws_path = WORKSPACE_ROOT / ws_name