diff --git a/pyproject.toml b/pyproject.toml
index 23215b53..1d3a8386 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -52,3 +52,4 @@ addopts = [
 
 [tool.mypy]
 check_untyped_defs = true
+disallow_incomplete_defs = true