diff --git a/web_theme_classic/pyproject.toml b/web_theme_classic/pyproject.toml
new file mode 100644
index 000000000..4231d0ccc
--- /dev/null
+++ b/web_theme_classic/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ["whool"]
+build-backend = "whool.buildapi"