{
  description = "hyperhive — multi-Claude-Code-agent orchestration on nixos-containers";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
    # Crane is stateless — no nixpkgs input to follow; `crane.mkLib
    # pkgs` returns the lib at whatever pkgs we pass it (we use the
    # project's pinned nixpkgs).
    crane.url = "github:ipetkov/crane";
    treefmt-nix = {
      url = "github:numtide/treefmt-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  # Thin entry point — the real logic lives under nix/:
  #   nix/sources.nix   filtered source views (meta-flake + docs inputs)
  #   nix/rust.nix      shared crane wiring (cleanSrc, cargoArtifacts)
  #   nix/packages/     every package output
  #   nix/checks.nix    flake checks
  #   nix/devshell.nix  dev shell
  #   nix/treefmt.nix   formatter config
  #   nix/host-modules/, nix/agent-modules/, nix/templates/  the NixOS module trees
  outputs =
    inputs@{
      self,
      nixpkgs,
      crane,
      treefmt-nix,
    }:
    let
      inherit (nixpkgs) lib;
      systems = [
        "aarch64-linux"
        "x86_64-linux"
      ];
      sources = import ./nix/sources.nix { inherit lib; };
      forAllSystems =
        f:
        lib.genAttrs systems (
          system:
          f rec {
            inherit system;
            pkgs = nixpkgs.legacyPackages.${system};
            treefmt-eval = treefmt-nix.lib.evalModule pkgs (import ./nix/treefmt.nix);
            craneLib = crane.mkLib pkgs;
            rust = import ./nix/rust.nix { inherit pkgs craneLib; };
          }
        );
    in
    {
      packages = forAllSystems (
        {
          pkgs,
          craneLib,
          rust,
          ...
        }:
        import ./nix/packages {
          inherit
            pkgs
            craneLib
            rust
            self
            nixpkgs
            ;
        }
      );

      nixosModules =
        let
          # Package wiring for agent containers — the harness modules
          # consume hyperhive's own packages via the `hyperhive.packages`
          # option (see nix/agent-modules/packages.nix); no overlay.
          # The `mkDefault` is applied PER KEY (`mapAttrs`), not to the
          # whole attrset: definition-level priority filtering runs
          # before `attrsOf`'s per-key merge, so a whole-set `mkDefault`
          # would be discarded entirely the moment an agent.nix
          # overrides a single key. Per-key priorities make an
          # individual override win while every other key keeps the
          # flake default.
          agentPackages =
            { lib, pkgs, ... }:
            {
              hyperhive.packages = lib.mapAttrs (_: lib.mkDefault) {
                inherit (self.packages.${pkgs.stdenv.hostPlatform.system})
                  hive-agent
                  hive-agent-mcp
                  hive-bash-daemon
                  hive-forge
                  hive-forge-notify
                  hive-github-notify
                  hive-matrix-daemon
                  hive-metric
                  hive-screen-mcp
                  assets
                  frontend
                  reference-docs
                  claude-plugins
                  ;
              };
            };
        in
        {
          agent-base.imports = [
            ./nix/templates/agent.nix
            agentPackages
          ];
          ruth.imports = [
            ./nix/templates/ruth.nix
            agentPackages
          ];
          # The full host stack (nix/host-modules/default.nix aggregator) plus
          # the package/source wiring from this flake. The wiring is a
          # plain config module setting the `services.hyperhive.c0re.*`
          # package options via `lib.mkDefault` — no overlay involved, and
          # an operator override still wins. Intended usage:
          #
          #   imports = [ hyperhive.nixosModules.default ];
          #   services.hyperhive.enable = true;
          #
          default =
            { lib, pkgs, ... }:
            {
              imports = [ ./nix/host-modules ];
              services.hyperhive.c0re = {
                package = lib.mkDefault self.packages.${pkgs.stdenv.hostPlatform.system}.default;
                frontend = lib.mkDefault self.packages.${pkgs.stdenv.hostPlatform.system}.frontend;
                assets = lib.mkDefault self.packages.${pkgs.stdenv.hostPlatform.system}.assets;
                xdgIcons = lib.mkDefault self.packages.${pkgs.stdenv.hostPlatform.system}.xdg-icons;
                hyperhiveFlake = lib.mkDefault "${sources.hyperhiveFlakeSource}";
                # Narrow docs/ source, threaded as its own meta-flake input
                # so doc edits don't re-hash the whole flake source.
                hyperhiveDocs = lib.mkDefault "${sources.hyperhiveDocsSource}";
                # Per-container toplevels — wired into
                # `system.extraDependencies` when
                # `services.hyperhive.c0re.preBuildAgentTemplates` is on so
                # the host system closure pre-fetches the heavy build
                # inputs. x86_64-linux only (nixosConfigurations are
                # hardcoded to that system); the gate keeps aarch64 hosts
                # from pulling them in via cross-build.
                agentBaseToplevel = lib.mkDefault self.packages.x86_64-linux.agent-base-toplevel;
                managerToplevel = lib.mkDefault self.packages.x86_64-linux.ruth-toplevel;
              };
              services.hyperhive.gateway.swaggerUiTheme =
                lib.mkDefault
                  self.packages.${pkgs.stdenv.hostPlatform.system}.swagger-ui-theme;
            };
          hive-ci = ./nix/host-modules/hive-ci.nix;
          hive-forge = ./nix/host-modules/hive-forge;
        };

      nixosConfigurations =
        let
          # These two configs are what hive-c0re extends per agent
          # (meta.rs's `mkAgent` does `<base>.extendModules { … }`, so
          # the built base and every container stay on one version).
          # Nothing deployment-specific may be set here: it would be
          # inherited by every container on the hive and collide with
          # the per-agent values hive-c0re renders. The agent modules
          # are written so a bare evaluation needs no such values —
          # service URLs default to `null`, meaning "not configured",
          # and the units that would use them simply aren't generated.
          mkContainer =
            module:
            nixpkgs.lib.nixosSystem {
              system = "x86_64-linux";
              modules = [ module ];
            };
        in
        {
          agent-base = mkContainer self.nixosModules.agent-base;
          ruth = mkContainer self.nixosModules.ruth;
        };

      devShells = forAllSystems ({ pkgs, rust, ... }: import ./nix/devshell.nix { inherit pkgs rust; });

      formatter = forAllSystems ({ treefmt-eval, ... }: treefmt-eval.config.build.wrapper);

      checks = forAllSystems (
        {
          pkgs,
          system,
          treefmt-eval,
          craneLib,
          rust,
          ...
        }:
        import ./nix/checks.nix {
          inherit
            pkgs
            craneLib
            rust
            self
            system
            treefmt-eval
            ;
        }
      );
    };
}