diff --git a/metagpt/actions/design_api.py b/metagpt/actions/design_api.py
index 4476e7c0a..86fa699bb 100644
--- a/metagpt/actions/design_api.py
+++ b/metagpt/actions/design_api.py
@@ -245,6 +245,7 @@ class WriteDesign(Action):
     ) -> str:
         prd_content = ""
         if prd_filename:
+            prd_filename = rectify_pathname(path=prd_filename, default_filename="prd.json")
             prd_content = await aread(filename=prd_filename)
         context = "### User Requirements\n{user_requirement}\n### Extra_info\n{extra_info}\n### PRD\n{prd}\n".format(
             user_requirement=to_markdown_code_block(user_requirement),
diff --git a/metagpt/actions/project_management.py b/metagpt/actions/project_management.py
index 2d54ffe08..abfea7f10 100644
--- a/metagpt/actions/project_management.py
+++ b/metagpt/actions/project_management.py
@@ -180,6 +180,7 @@ class WriteTasks(Action):
     ) -> str:
         context = to_markdown_code_block(user_requirement)
         if design_filename:
+            design_filename = rectify_pathname(path=design_filename, default_filename="system_design.json")
             content = await aread(filename=design_filename)
             context += to_markdown_code_block(content)