diff --git a/cli/assets/scripts/design_system.py b/cli/assets/scripts/design_system.py
index d3152e5..339aaba 100644
--- a/cli/assets/scripts/design_system.py
+++ b/cli/assets/scripts/design_system.py
@@ -573,8 +573,9 @@ def persist_design_system(design_system: dict, page: str = None, output_dir: str
     """
     base_dir = Path(output_dir) if output_dir else Path.cwd()
     
-    # Use project name for project-specific folder
-    project_name = design_system.get("project_name", "default")
+    # Use project name for project-specific folder. Coalesce falsy values
+    # (missing key, explicit None, or "") so the .lower() below can't crash.
+    project_name = design_system.get("project_name") or "default"
     project_slug = project_name.lower().replace(' ', '-')
     
     design_system_dir = base_dir / "design-system" / project_slug
diff --git a/src/ui-ux-pro-max/scripts/design_system.py b/src/ui-ux-pro-max/scripts/design_system.py
index d3152e5..339aaba 100644
--- a/src/ui-ux-pro-max/scripts/design_system.py
+++ b/src/ui-ux-pro-max/scripts/design_system.py
@@ -573,8 +573,9 @@ def persist_design_system(design_system: dict, page: str = None, output_dir: str
     """
     base_dir = Path(output_dir) if output_dir else Path.cwd()
     
-    # Use project name for project-specific folder
-    project_name = design_system.get("project_name", "default")
+    # Use project name for project-specific folder. Coalesce falsy values
+    # (missing key, explicit None, or "") so the .lower() below can't crash.
+    project_name = design_system.get("project_name") or "default"
     project_slug = project_name.lower().replace(' ', '-')
     
     design_system_dir = base_dir / "design-system" / project_slug