diff --git a/metagpt/actions/write_code.py b/metagpt/actions/write_code.py
index c1d56f523..77976a696 100644
--- a/metagpt/actions/write_code.py
+++ b/metagpt/actions/write_code.py
@@ -123,7 +123,7 @@ class WriteCode(Action):
         else:
             code_context = await self.get_codes(coding_context.task_doc, exclude=self.context.filename)
 
-        if guideline:  # guide write code 也有两种方式，进行尝试
+        if guideline:
             prompt = WRITE_CODE_INCREMENT_TEMPLATE.format(
                 guideline=guideline,
                 design=coding_context.design_doc.content if coding_context.design_doc else "",
@@ -165,17 +165,17 @@ class WriteCode(Action):
         src_file_repo = CONFIG.git_repo.new_file_repository(relative_path=CONFIG.src_workspace)
 
         if mode == "guide":
-            # 从两个repo中取code，并结合在一起
             src_files = src_file_repo.all_files
             old_file_repo = CONFIG.git_repo.new_file_repository(relative_path=CONFIG.old_workspace)
             old_files = old_file_repo.all_files
             union_files_list = list(set(src_files) | set(old_files))
             for filename in union_files_list:
                 if filename == exclude:
-                    if filename in old_files:
+                    if filename in old_files and filename != "main.py":
                         doc = await old_file_repo.get(filename=filename)  # 使用原始代码
                     else:
                         continue
+                    codes.append(f"----- Legacy {filename}\n```{doc.content}```")
 
                 else:
                     doc = await src_file_repo.get(filename=filename)  # 使用先前生成的代码
@@ -185,7 +185,7 @@ class WriteCode(Action):
                         # else:
                         #     continue
                         continue  # 跳过
-                codes.append(f"----- {filename}\n```{doc.content}```")
+                    codes.append(f"----- {filename}\n```{doc.content}```")
 
         else:
             for filename in code_filenames:
diff --git a/metagpt/actions/write_code_guide_an.py b/metagpt/actions/write_code_guide_an.py
index 579008732..8bf7da1a6 100644
--- a/metagpt/actions/write_code_guide_an.py
+++ b/metagpt/actions/write_code_guide_an.py
@@ -18,10 +18,10 @@ from metagpt.schema import Document
 GUIDELINE = ActionNode(
     key="Code Guideline",
     expected_type=list[str],
-    instruction="crafting comprehensive incremental development plans and providing detailed code guidance",
+    instruction="Developing comprehensive and incremental software development plans while providing detailed code guidance.",
     example=[
-        "`calculator.py` should be extended to include methods for subtraction, multiplication, and division. Error handling should be implemented for division to prevent division by zero.",
-        "New endpoints for subtraction, multiplication, and division should be added to `main.py`.",
+        "Enhance the functionality of `calculator.py` by extending it to incorporate methods for subtraction, multiplication, and division. Implement robust error handling for the division operation to mitigate potential issues related to division by zero.",
+        "Integrate new API endpoints for subtraction, multiplication, and division into the existing codebase of `main.py`. Ensure seamless integration with the overall application architecture and maintain consistency with coding standards.",
     ],
 )
 
@@ -155,10 +155,11 @@ ATTENTION: Use '##' to SPLIT SECTIONS, not '#'. Output format carefully referenc
 2. COMPLETE CODE: Your code will be part of the entire project, so please implement complete, reliable, reusable code snippets.
 3. Set default value: If there is any setting, ALWAYS SET A DEFAULT VALUE, ALWAYS USE STRONG TYPE AND EXPLICIT VARIABLE. AVOID circular import.
 4. Follow design: YOU MUST FOLLOW "Data structures and interfaces". DONT CHANGE ANY DESIGN. Do not use public member functions that do not exist in your design.
-5. CAREFULLY CHECK THAT YOU DONT MISS ANY NECESSARY CLASS/FUNCTION IN THIS FILE.
-6. Before using a external variable/module, make sure you import it first.
-7. Write out EVERY CODE DETAIL, DON'T LEAVE TODO.
-8. Attention: Make modifications and additions to the legacy code in accordance with the provided guidelines and API. Ensure that the complete code is implemented without any omissions. 
+5. Follow Guideline: If Legacy Code files contain {filename}, you are required to follow the Guideline to merge the Incremental Change into the Legacy {filename} file when rewriting {filename} file. 
+6. CAREFULLY CHECK THAT YOU DONT MISS ANY NECESSARY CLASS/FUNCTION IN THIS FILE.
+7. Before using a external variable/module, make sure you import it first.
+8. Write out EVERY CODE DETAIL, DON'T LEAVE TODO.
+9. Attention: Implement the functionality required within the current file's scope, reusing existing code whenever possible. For instance, main.py achieves its purpose by instantiating an already implemented class, rather than manually implementing a class in main.py.
 """
 
 CODE_GUIDE_CONTEXT_EXAMPLE = """
diff --git a/metagpt/roles/engineer.py b/metagpt/roles/engineer.py
index 165ffadc2..2eee4c477 100644
--- a/metagpt/roles/engineer.py
+++ b/metagpt/roles/engineer.py
@@ -80,7 +80,6 @@ class Engineer(Role):
     )
     n_borg: int = 1
     use_code_review: bool = False
-    use_code_guide: bool = True
     code_todos: list = []
     summarize_todos = []
 
@@ -138,7 +137,7 @@ class Engineer(Role):
         return None
 
     async def _act_write_code(self):
-        if self.use_code_guide:
+        if CONFIG.inc:
             code_guideline = await self._write_code_guideline()
             changed_files = await self._act_sp_with_cr(review=self.use_code_review, guideline=code_guideline)
         else: