{
  description = "alexion.dev";

  inputs = {
    # Base nixpkgs channel.
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

    # Fresher packages, reachable per-package as `unstable.<name>`.
    nixpkgs-unstable.url = "github:nixos/nixpkgs/nixpkgs-unstable";

    # Latest stable release, reachable per-package as `stable.<name>`.
    nixpkgs-stable.url = "github:nixos/nixpkgs/nixos-26.05";

    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Signed AMO extensions, pinned by version and hash.
    firefox-addons = {
      url = "gitlab:rycee/nur-expressions?dir=pkgs/firefox-addons";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Follows our nixpkgs so its plugins build against the same package set.
    nixvim = {
      url = "github:nix-community/nixvim";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Declarative disk partitioning.
    # Each host declares its own layout.
    disko = {
      url = "github:nix-community/disko";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Upstream per-machine hardware profiles.
    # Each host imports its own.
    nixos-hardware = {
      url = "github:NixOS/nixos-hardware";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Decrypts committed secrets at activation, from an age identity on the host.
    sops-nix = {
      url = "github:Mic92/sops-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Themes the graphical layer from one base16 scheme.
    # Follows our nixpkgs so it themes the same package set the host builds.
    stylix = {
      url = "github:danth/stylix";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # TODO: deprecate / remove
    # Agent-ergonomic CLI for Gitea, with a home-manager module for the agent context.
    gitea-axi = {
      url = "git+https://git.alexion.dev/alexion/gitea-axi";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Repository formatter and Nix lint wiring.
    treefmt-nix = {
      url = "github:numtide/treefmt-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # CachyOS kernel and binary cache.
    # This must not follow this flake's nixpkgs because Chaotic builds against its own pinned package set.
    # Its cache serves the kernel only when the overlay stays on the cache-friendly path.
    chaotic.url = "github:chaotic-cx/nyx/nyxpkgs-unstable";
  };

  outputs =
    { self, nixpkgs, ... }@inputs:
    import ./src/flake {
      inherit inputs self;
      inherit (nixpkgs) lib;
      root = ./.;
      system = "x86_64-linux";
    };
}