diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 429f2ede..cf607219 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -46,7 +46,7 @@ jobs:
       - name: Setup mypy
         run: yes | poetry run mypy cashu --install-types || true
       - name: Run mypy
-        run: poetry run mypy cashu --ignore-missing
+        run: poetry run mypy cashu --ignore-missing --check-untyped-defs
   ruff:
     runs-on: ubuntu-latest
     steps: