diff --git a/examples/debate.py b/examples/debate.py
index 8f5012d66..630f78cd8 100644
--- a/examples/debate.py
+++ b/examples/debate.py
@@ -15,7 +15,6 @@ from metagpt.logs import logger
 from metagpt.roles import Role
 from metagpt.schema import Message
 from metagpt.software_company import SoftwareCompany
-from metagpt.utils.common import any_to_str_set
 
 
 class ShoutOut(Action):
@@ -66,7 +65,7 @@ class Trump(Role):
     async def _act(self) -> Message:
         logger.info(f"{self._setting}: ready to {self._rc.todo}")
 
-        msg_history = self._rc.memory.get_by_actions(any_to_str_set([ShoutOut]))
+        msg_history = self._rc.memory.get_by_actions([ShoutOut])
         context = []
         for m in msg_history:
             context.append(str(m))
@@ -108,7 +107,7 @@ class Biden(Role):
     async def _act(self) -> Message:
         logger.info(f"{self._setting}: ready to {self._rc.todo}")
 
-        msg_history = self._rc.memory.get_by_actions(any_to_str_set([BossRequirement, ShoutOut]))
+        msg_history = self._rc.memory.get_by_actions([BossRequirement, ShoutOut])
         context = []
         for m in msg_history:
             context.append(str(m))
diff --git a/metagpt/memory/memory.py b/metagpt/memory/memory.py
index 71d999049..53b65fcf7 100644
--- a/metagpt/memory/memory.py
+++ b/metagpt/memory/memory.py
@@ -10,6 +10,7 @@ from collections import defaultdict
 from typing import Iterable, Set
 
 from metagpt.schema import Message
+from metagpt.utils.common import any_to_str, any_to_str_set
 
 
 class Memory:
@@ -73,14 +74,16 @@ class Memory:
             news.append(i)
         return news
 
-    def get_by_action(self, action: str) -> list[Message]:
+    def get_by_action(self, action) -> list[Message]:
         """Return all messages triggered by a specified Action"""
-        return self.index[action]
+        index = any_to_str(action)
+        return self.index[index]
 
     def get_by_actions(self, actions: Set) -> list[Message]:
         """Return all messages triggered by specified Actions"""
         rsp = []
-        for action in actions:
+        indices = any_to_str_set(actions)
+        for action in indices:
             if action not in self.index:
                 continue
             rsp += self.index[action]
diff --git a/metagpt/roles/engineer.py b/metagpt/roles/engineer.py
index 742e00cc8..960f9c0f3 100644
--- a/metagpt/roles/engineer.py
+++ b/metagpt/roles/engineer.py
@@ -21,7 +21,7 @@ from metagpt.const import WORKSPACE_ROOT
 from metagpt.logs import logger
 from metagpt.roles import Role
 from metagpt.schema import Message
-from metagpt.utils.common import CodeParser, any_to_str, any_to_str_set
+from metagpt.utils.common import CodeParser, any_to_str
 from metagpt.utils.special_tokens import FILENAME_CODE_SEP, MSG_SEP
 
 
@@ -102,7 +102,7 @@ class Engineer(Role):
         return CodeParser.parse_str(block="Python package name", text=system_design_msg.content)
 
     def get_workspace(self) -> Path:
-        msg = self._rc.memory.get_by_action(any_to_str(WriteDesign))[-1]
+        msg = self._rc.memory.get_by_action(WriteDesign)[-1]
         if not msg:
             return WORKSPACE_ROOT / "src"
         workspace = self.parse_workspace(msg)
@@ -130,7 +130,7 @@ class Engineer(Role):
         todo_coros = []
         for todo in self.todos:
             todo_coro = WriteCode().run(
-                context=self._rc.memory.get_by_actions(any_to_str_set([WriteTasks, WriteDesign])),
+                context=self._rc.memory.get_by_actions([WriteTasks, WriteDesign]),
                 filename=todo,
             )
             todo_coros.append(todo_coro)
@@ -185,7 +185,7 @@ class Engineer(Role):
             TODO: The goal is not to need it. After clear task decomposition, based on the design idea, you should be able to write a single file without needing other codes. If you can't, it means you need a clearer definition. This is the key to writing longer code.
             """
             context = []
-            msg = self._rc.memory.get_by_actions(any_to_str_set([WriteDesign, WriteTasks, WriteCode]))
+            msg = self._rc.memory.get_by_actions([WriteDesign, WriteTasks, WriteCode])
             for m in msg:
                 context.append(m.content)
             context_str = "\n".join(context)
@@ -240,8 +240,7 @@ class Engineer(Role):
 
     async def _think(self) -> None:
         # In asynchronous scenarios, first check if the required messages are ready.
-        filters = {any_to_str(WriteTasks)}
-        msgs = self._rc.memory.get_by_actions(filters)
+        msgs = self._rc.memory.get_by_actions({WriteTasks})
         if not msgs:
             self._rc.todo = None
             return
diff --git a/metagpt/roles/qa_engineer.py b/metagpt/roles/qa_engineer.py
index 38fb5a24b..9495e1a12 100644
--- a/metagpt/roles/qa_engineer.py
+++ b/metagpt/roles/qa_engineer.py
@@ -22,12 +22,7 @@ from metagpt.const import WORKSPACE_ROOT
 from metagpt.logs import logger
 from metagpt.roles import Role
 from metagpt.schema import Message
-from metagpt.utils.common import (
-    CodeParser,
-    any_to_str_set,
-    get_class_name,
-    parse_recipient,
-)
+from metagpt.utils.common import CodeParser, any_to_str, any_to_str_set, parse_recipient
 from metagpt.utils.special_tokens import FILENAME_CODE_SEP, MSG_SEP
 
 
@@ -55,7 +50,7 @@ class QaEngineer(Role):
         return CodeParser.parse_str(block="Python package name", text=system_design_msg.content)
 
     def get_workspace(self, return_proj_dir=True) -> Path:
-        msg = self._rc.memory.get_by_action(get_class_name(WriteDesign))[-1]
+        msg = self._rc.memory.get_by_action(WriteDesign)[-1]
         if not msg:
             return WORKSPACE_ROOT / "src"
         workspace = self.parse_workspace(msg)
@@ -104,7 +99,7 @@ class QaEngineer(Role):
             msg = Message(
                 content=str(file_info),
                 role=self.profile,
-                cause_by=WriteTest,
+                cause_by=any_to_str(WriteTest),
                 sent_from=self.profile,
                 send_to=self.profile,
             )