diff --git a/flake.nix b/flake.nix
index ef4c38b..94a8af6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,13 +5,20 @@
 
   outputs = { self, nixpkgs }: let
     system = "x86_64-linux";
+    inherit (nixpkgs) lib;
     pkgs = nixpkgs.legacyPackages.${system};
   in {
     packages.${system} = {
       default = self.packages.${system}.pvv-calendar-bot;
       pvv-calendar-bot = pkgs.python3Packages.buildPythonPackage {
         name = "pvv-calendar-bot";
-        src = ./.;
+        src = lib.fileset.toSource {
+          root = ./.;
+          fileset = lib.fileset.unions [
+            ./pyproject.toml
+            ./src
+          ];
+        };
         pyproject = true;
 
         build-system = [ pkgs.python3Packages.setuptools ];