{
  description = "sift: LLM-oriented fetch and search";

  inputs.nixpkgs.url = "nixpkgs/nixos-26.05";

  outputs =
    { self, nixpkgs }:
    let
      systems = [ "x86_64-linux" ];
      forAllSystems = nixpkgs.lib.genAttrs systems;
      version =
        if self ? shortRev then
          self.shortRev
        else if self ? dirtyShortRev then
          self.dirtyShortRev
        else
          "dev";
      # Keep in lockstep with Makefile LDFLAGS / -trimpath.
      ldflags = [
        "-s"
        "-w"
        "-X"
        "main.version=${version}"
      ];
    in
    {
      packages = forAllSystems (
        system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
          sift = pkgs.buildGoModule {
            pname = "sift";
            inherit version;
            src = ./.;
            vendorHash = "sha256-byOhTmZTW76qEyv8PyuCtbj2C+nk894nPyuwjhFJqtk=";
            env.CGO_ENABLED = "0";
            ldflags = ldflags;
            subPackages = [ "cmd/sift" ];
            # buildGoModule already passes -trimpath.
            meta = {
              description = "LLM-oriented fetch and search";
              mainProgram = "sift";
            };
          };
        in
        {
          inherit sift;
          default = sift;
        }
      );

      nixosModules.sift =
        { pkgs, ... }:
        {
          imports = [ ./nix/module.nix ];
          services.sift.package = nixpkgs.lib.mkDefault self.packages.${pkgs.stdenv.hostPlatform.system}.sift;
        };
      nixosModules.default = self.nixosModules.sift;

      checks = forAllSystems (
        system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
          src = ./.;
        in
        {
          test = pkgs.stdenv.mkDerivation {
            name = "sift-make-test-lint";
            inherit src;
            nativeBuildInputs = [
              pkgs.go
              pkgs.gcc
              pkgs.gnumake
              pkgs.git
            ];
            dontConfigure = true;
            buildPhase = ''
              export HOME=$TMPDIR
              export GOCACHE=$TMPDIR/go-cache
              export GOPATH=$TMPDIR/go
              export GO111MODULE=on
              export GOPROXY=off
              export GOFLAGS=-mod=vendor
              # race detector needs cgo; build stays CGO_ENABLED=0 in packages.sift
              export CGO_ENABLED=1
              make test lint
            '';
            installPhase = ''
              mkdir -p $out
              echo ok > $out/ok
            '';
          };
        }
      );

      devShells = forAllSystems (
        system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
        in
        {
          default = pkgs.mkShell {
            nativeBuildInputs = [
              pkgs.go
              pkgs.gopls
              pkgs.go-tools
              pkgs.gnumake
              pkgs.git
            ];
          };
        }
      );
    };
}