{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
    weyl-std.url = "github:weyl-ai/weyl-std";
  };

  outputs = inputs@{ flake-parts, weyl-std, ... }:
    flake-parts.lib.mkFlake { inherit inputs; } {
      imports = [ weyl-std.flakeModules.default ];

      # weyl-std configuration
      weyl-std = {
        formatter.enable = true;
        devshell.enable = true;
      };

      perSystem = { config, pkgs, ... }:
        let
          P = config.weyl.prelude;
        in {
          packages.default = P.stdenv.default {
            pname = "my-app";
            version = "1.0";
            src = ./.;
          };
        };
    };
}

imports = [ weyl-std.flakeModules.default ];

imports = [
  weyl-std.flakeModules.formatter  # treefmt-nix with opinionated defaults
  weyl-std.flakeModules.nixpkgs    # nixpkgs config
  weyl-std.flakeModules.std        # overlays (includes prelude + nvidia-sdk)
  weyl-std.flakeModules.prelude    # prelude flake-module only
  weyl-std.flakeModules.devshell   # Development shell
  weyl-std.flakeModules.docs       # Documentation generation
];

perSystem = { config, ... }:
  let
    P = config.weyl.prelude;
  in {
    # Functional library
    example = P.map (x: x * 2) [ 1 2 3 ];  # [ 2 4 6 ]

    # Stdenvs
    packages.my-app = P.stdenv.default {
      pname = "my-app";
      version = "1.0";
      src = ./.;
    };

    # Language toolchains
    packages.py-app = P.python.app {
      pname = "py-app";
      version = "1.0";
      src = ./.;
    };
  };

perSystem = { config, ... }:
  let
    P = config.weyl.prelude;
  in {
    packages.my-app = P.stdenv.default {
      pname = "my-app";
      version = "1.0";
      src = ./.;
      build-phase = ''
        $CXX -o app src/main.cpp
        install -D app $out/bin/app
      '';
    };
  };

packages.nvidia-kernel = P.stdenv.nvidia {
  pname = "nvidia-kernel";
  version = "1.0";
  src = ./.;
  build-phase = ''
    $CXX -o kernel src/kernel.cu
    install -D kernel $out/bin/kernel
  '';
};

packages.static-tool = P.stdenv.portable {
  pname = "static-tool";
  version = "1.0";
  src = ./.;
  # Result: single static binary, runs anywhere
};

packages.arm-binary = P.cross.aarch64 {
  name = "arm-app";
  src = ./.;
};

packages.grace-hopper = P.cross.grace {
  name = "grace-app";
  src = ./.;
  # Targets aarch64 + Hopper GPU
};

weyl-std.devshell = {
  enable = true;
  nvidia.enable = true;  # Include NVIDIA SDK
  extra-packages = pkgs: [ pkgs.ripgrep ];
};

weyl-std.formatter = {
  enable = true;
  line-length = 100;
  indent-width = 2;
};

perSystem = { pkgs, ... }: {
  # Via overlay (pkgs must have weyl-std overlay applied)
  packages.my-app = pkgs.weyl.stdenv.default {
    pname = "my-app";
    version = "1.0";
    src = ./.;
  };
};