diff --git a/metagpt/tools/libs/editor.py b/metagpt/tools/libs/editor.py
index fcf892fdb..94836a9fe 100644
--- a/metagpt/tools/libs/editor.py
+++ b/metagpt/tools/libs/editor.py
@@ -165,7 +165,7 @@ class Editor:
                 # irrespective of the length difference between the original and new content.
                 lines[start_line_index:end_line_index] = new_content_lines
             else:
-                lines.insert(start_line_index, "\n".join(new_content_lines))
+                lines.insert(start_line_index, "".join(new_content_lines))
         else:
             del lines[start_line_index:end_line_index]