{ inputs, ... }: {
  imports = [
    inputs.treefmt-nix.flakeModule
  ];
  perSystem = { pkgs, ... }: {
    treefmt = {
      projectRootFile = ".git/config";
      programs.nixpkgs-fmt.enable = true;
      programs.shellcheck.enable = true;
      programs.deno.enable = true;
      settings.formatter.shellcheck.options = [ "-s" "bash" ];

      programs.mypy = {
        enable = true;
        directories.".".extraPythonPackages = [
          pkgs.python3.pkgs.twisted
        ];
      };
      settings.formatter.python = {
        command = "sh";
        options = [
          "-eucx"
          ''
            ${pkgs.ruff}/bin/ruff --fix "$@"
            ${pkgs.ruff}/bin/ruff format "$@"
          ''
          "--" # this argument is ignored by bash
        ];
        includes = [ "*.py" ];
      };
    };
  };
}