diff --git a/metagpt/roles/engineer.py b/metagpt/roles/engineer.py
index ba622429b..62e1e92d2 100644
--- a/metagpt/roles/engineer.py
+++ b/metagpt/roles/engineer.py
@@ -21,7 +21,12 @@ 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, get_class_name, get_object_name
+from metagpt.utils.common import (
+    CodeParser,
+    any_to_str_set,
+    get_class_name,
+    get_object_name,
+)
 from metagpt.utils.special_tokens import FILENAME_CODE_SEP, MSG_SEP
 
 
@@ -102,7 +107,7 @@ 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(WriteDesign)[-1]
+        msg = self._rc.memory.get_by_action(get_class_name(WriteDesign))[-1]
         if not msg:
             return WORKSPACE_ROOT / "src"
         workspace = self.parse_workspace(msg)
@@ -130,7 +135,7 @@ class Engineer(Role):
         todo_coros = []
         for todo in self.todos:
             todo_coro = WriteCode().run(
-                context=self._rc.memory.get_by_actions([WriteTasks, WriteDesign]),
+                context=self._rc.memory.get_by_actions(any_to_str_set([WriteTasks, WriteDesign])),
                 filename=todo,
             )
             todo_coros.append(todo_coro)
@@ -185,7 +190,7 @@ 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([WriteDesign, WriteTasks, WriteCode])
+            msg = self._rc.memory.get_by_actions(any_to_str_set([WriteDesign, WriteTasks, WriteCode]))
             for m in msg:
                 context.append(m.content)
             context_str = "\n".join(context)
diff --git a/metagpt/roles/qa_engineer.py b/metagpt/roles/qa_engineer.py
index 760b65736..38fb5a24b 100644
--- a/metagpt/roles/qa_engineer.py
+++ b/metagpt/roles/qa_engineer.py
@@ -22,7 +22,12 @@ 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, parse_recipient
+from metagpt.utils.common import (
+    CodeParser,
+    any_to_str_set,
+    get_class_name,
+    parse_recipient,
+)
 from metagpt.utils.special_tokens import FILENAME_CODE_SEP, MSG_SEP
 
 
@@ -50,7 +55,7 @@ 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(WriteDesign)[-1]
+        msg = self._rc.memory.get_by_action(get_class_name(WriteDesign))[-1]
         if not msg:
             return WORKSPACE_ROOT / "src"
         workspace = self.parse_workspace(msg)
diff --git a/metagpt/roles/role.py b/metagpt/roles/role.py
index f3e11b294..b8be309bb 100644
--- a/metagpt/roles/role.py
+++ b/metagpt/roles/role.py
@@ -217,9 +217,11 @@ class Role:
     async def _observe(self) -> int:
         """Prepare new messages for processing from the message buffer and other sources."""
         # Read unprocessed messages from the msg buffer.
-        self._rc.news = self._rc.msg_buffer.pop_all()
+        news = self._rc.msg_buffer.pop_all()
         # Store the read messages in your own memory to prevent duplicate processing.
-        self._rc.memory.add_batch(self._rc.news)
+        self._rc.memory.add_batch(news)
+        # Filter out messages of interest.
+        self._rc.news = [n for n in news if n.cause_by in self._rc.watch]
 
         # Design Rules:
         # If you need to further categorize Message objects, you can do so using the Message.set_meta function.
diff --git a/requirements.txt b/requirements.txt
index 24a2d94c3..c3b909e77 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,7 +14,7 @@ langchain==0.0.231
 loguru==0.6.0
 meilisearch==0.21.0
 numpy==1.24.3
-openai
+openai==0.28.1
 openpyxl
 beautifulsoup4==4.12.2
 pandas==2.0.3