diff --git a/flake.nix b/flake.nix
index aaf1bd2..2cdee1f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -68,7 +68,7 @@
             checkInputs = [ pkgs.inventoryDevEnv ];
             checkPhase = ''
               mkdir -p $out
-              mypy src/
+              cd src/ && mypy --config-file=../pyproject.toml .
               flake8 . --count --show-source --statistics
             '';
           };