diff --git a/.ci/mypy.sh b/.ci/mypy.sh
index fccf66e91a1acbc3ae50658a22f7332d7c370ce1..bcebb0a600b097a07b3a23b407e446758bda7158 100755
--- a/.ci/mypy.sh
+++ b/.ci/mypy.sh
@@ -11,4 +11,4 @@ fi
 set -x
 
 pip install --break-system-packages --no-warn-script-location mypy
-python -m mypy --color-output --check-untyped-defs pmbootstrap.py
+python -m mypy --color-output pmbootstrap.py
diff --git a/pyproject.toml b/pyproject.toml
index d191fb2f9fe63ef2a64e1785e4916c9eacc17881..23215b536d9e756e567c14814f330a5f172a601b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,3 +50,5 @@ addopts = [
     "--basetemp=.pytest_tmp"
 ]
 
+[tool.mypy]
+check_untyped_defs = true