diff --git a/.tangled/workflows/fmt.yml b/.tangled/workflows/fmt.yml
--- a/.tangled/workflows/fmt.yml
+++ b/.tangled/workflows/fmt.yml
@@ -9,4 +9,4 @@ - name: "Check formatting"
     command: |
       mkdir -p bobbin/crates/types/src/_lex
       [ -f bobbin/crates/types/src/_lex/lib.rs ] || : > bobbin/crates/types/src/_lex/lib.rs
-      nix run .#fmt -- --ci
+      nix fmt -- --ci
diff --git a/flake.nix b/flake.nix
--- a/flake.nix
+++ b/flake.nix
@@ -261,10 +261,6 @@ export BROWSERSLIST_IGNORE_OLD_DATA=true
           ${pkgs.tailwindcss}/bin/tailwindcss --watch=always -i input.css -o ./appview/pages/static/tw.css
         '';
     in {
-      fmt = {
-        type = "app";
-        program = pkgs.lib.getExe packages'.treefmt-wrapper;
-      };
       watch-appview = {
         type = "app";
         program = toString (pkgs.writeShellScript "watch-appview" ''
@@ -405,5 +401,7 @@ imports = [./nix/modules/spindle.nix];
 
       services.tangled.spindle.package = lib.mkDefault self.packages.${pkgs.stdenv.hostPlatform.system}.spindle;
     };
+
+    formatter = forAllSystems (system: self.packages.${system}.treefmt-wrapper);
   };
 }