Maybe fix overlay?

flake.nix

@@ -11,6 +11,12 @@
   };
 
   outputs = { self, nixpkgs, flake-utils, poetry2nix }:
+    {
+      overlays.default = final: prev: {
+        huecli = self.packages.${prev.system}.default;
+      };
+    }
+    //
     flake-utils.lib.eachDefaultSystem (system:
       let
         # see https://github.com/nix-community/poetry2nix/tree/master#api for more functions and examples.
@@ -30,9 +36,6 @@
         );
       in
       {
-        overlays.default = final: prev: {
-          huecli = self.packages.${prev.system}.default;
-        };
         packages = {
           huecli = mkPoetryApplication {
             projectDir = ./.;
@@ -48,25 +51,12 @@
           default = self.packages.${system}.huecli;
         };
 
-        # Shell for app dependencies.
-        #
-        #     nix develop
-        #
-        # Use this shell for developing your app.
         devShells.default = pkgs.mkShell {
           inputsFrom = [ self.packages.${system}.huecli ];
           packages = [
             pkgs.ruff
+            pkgs.poetry
           ];
         };
-
-        # Shell for poetry.
-        #
-        #     nix develop .#poetry
-        #
-        # Use this shell for changes to pyproject.toml and poetry.lock.
-        devShells.poetry = pkgs.mkShell {
-          packages = [ pkgs.poetry ];
-        };
       });
 }