diff --git a/pyproject.toml b/pyproject.toml
index 7161e96..e22c0e5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,6 +2,9 @@
 requires = ["setuptools"]
 build-backend = "setuptools.build_meta"
 
+[tool.setuptools]
+packages = ["einx"]
+
 [project]
 name = "einx"
 version = "0.3.0"