diff --git a/scripts/create_template_db.py b/scripts/create_template_db.py
index 46b662df9..136d103bb 100644
--- a/scripts/create_template_db.py
+++ b/scripts/create_template_db.py
@@ -10,6 +10,7 @@ Usage:
 Default output: build/.template-migrated.db
 """
 
+import os
 import sys
 from pathlib import Path
 
@@ -62,6 +63,11 @@ def create_template(output_path: str = "build/.template-migrated.db") -> None:
 
     engine.dispose()
 
+    # Ensure the template database is writable (0o664 = rw-rw-r--)
+    # This prevents sqlite3.OperationalError: attempt to write a readonly database
+    # when tests copy and modify the template during test setup.
+    os.chmod(str(out), 0o664)
+
 
 if __name__ == "__main__":
     path = sys.argv[1] if len(sys.argv) > 1 else "build/.template-migrated.db"