NixOS Configuration

My NixOS configuration using Den, flake-parts, and import-tree.

Structure

Path	Purpose
modules/hosts.nix	Host attributes and user assignments
modules/hosts/<host>/default.nix	Host aspects and hardware-specific settings
modules/users/<user>/<user>.nix	User aspects and included features
modules/<category>/	Reusable aspects, one file per aspect
hosts/<host>/hardware-configuration.nix	Generated hardware configuration
assets/	Images, scripts, shaders, and editable application settings
secrets/	SOPS-encrypted secrets and setup instructions
modules/flake-inputs.nix	Flake inputs; flake.nix is generated

All .nix files under modules/ are discovered automatically. An aspect becomes active when included by a host, user, or bundle. Host-specific values belong in host attributes; personal values belong in user attributes in modules/hosts.nix.

Hosts and included aspects

Host	Hardware	Host includes
void	Ryzen 9 9950X, RX 9070 XT, three monitors	base-system, wireguard, gaming
voidframe	Framework laptop, Ryzen 7 7840U	base-system

Both hosts use the neonvoid user aspect. Den applies the user aspect automatically; do not also include it in the host aspect. Host bundles project their Home Manager settings to users through den._.host-aspects.

System bundles

Bundle	Included aspects
base-system — core	boot, locale, networking, systemd, overlays, nix-settings, multiverse
base-system — hardware	bluetooth, kernel, print, udev
base-system — security	sops, pcscd, sudo, noctalia-greeter, polkit
base-system — services/packages	ananicy, system-packages
gaming — desktop only	steam, mangohud, deadlock, wow, scopebuddy

User includes — defined in neonvoid.nix.

Category	Included aspects
Shell tools	bat, btop, direnv, devenv, delta, eza, fastfetch, fzf, git, kitty, just, lazygit, mcp, nh, nix-index, nvim, opencode, pay-respects, starship, tealdeer, yazi, zoxide, zsh
Desktop	desktop-environment, fonts, xdg, stylix, noctalia, flatpak, clipboard, cursor, firefox, gtk, umbriel, thunar, xembsni
Services	gnome-keyring, pipewire, streamcontroller, usb
Home	common, files, packages
Media	cava, easyeffects, mpv, obs-studio, pics, youtube-music
Communication	discord, email

Adding a host

1. Add a host entry under den.hosts.x86_64-linux in modules/hosts.nix. Reuse the existing neonvoid attrset or assign another user:

myhost = {
  users.neonvoid = neonvoid;
  timezone = "America/New_York";
  greeting = "My Host";
  xRes = "1920";
  yRes = "1080";
  monitors.main = {
    name = "DP-1";
    mode = "1920x1080@60";
    scale = 1.0;
    position = "0x0";
    primary = true;
  };
};

2. Create modules/hosts/myhost/default.nix:

{ den, inputs, ... }:
{
  den.aspects.myhost = {
    includes = [ den.aspects.base-system ];
    nixos = {
      imports = [ (inputs.self + "/hosts/myhost/hardware-configuration.nix") ];
      # Add this machine's boot, hardware, and networking settings here.
    };
  };
}

3. Add hosts/myhost/hardware-configuration.nix from nixos-generate-config.
4. Prepare the machine's secrets using secrets/README.md, stage new files, and validate with nix flake check.

Den creates nixosConfigurations.myhost automatically. For additional host attributes such as audio, network, printer, gamesLocation, and gaming.environment, use the existing entries in modules/hosts.nix as examples.

Adding a user

1. Create modules/users/myuser/myuser.nix and select the aspects they need:

{ den, ... }:
{
  den.aspects.myuser = {
    includes = [
      den.aspects.common
      den.aspects.files
      den.aspects.zsh
      den.aspects.git
    ];
    nixos.users.users.myuser.extraGroups = [ "audio" "video" ];
  };
}

2. Assign the user in the relevant host entry in modules/hosts.nix:

users.myuser = {
  gitName = "My Name";
  gitEmail = "me@example.com";
};

3. Stage new files and validate with nix flake check.

Optional user attributes include avatar, logo, wallpaperRepository, and emailAccounts. Email accounts can use plain address/userName values or SOPS-backed addressSecret/userNameSecret references; see the secret setup guide.

Adding an aspect

Create modules/<category>/<name>.nix defining den.aspects.<name>, then add it to a user, host, or bundle's includes. Keep NixOS and Home Manager configuration for the same feature in that file. Update this README when changing the structure or included aspects.

Commands

Run on x86_64-linux, or use a compatible builder for Linux checks and builds:

nix flake check             # Validate
nh os build                # Build without activating
nh os switch               # Deploy manually
nix flake update           # Update locked inputs
treefmt                    # Format Nix files

After editing modules/flake-inputs.nix, regenerate flake.nix on Linux with j write-flake. To run from a checkout before the global justfile is updated:

just --justfile assets/justfile write-flake

Cache URLs and keys live in assets/nix/caches.nix. After changing them, run j write-flake before building so the generated flake applies them during the build. Both hosts accept flake settings through their NixOS configuration. The first rebuild that installs this setting needs a one-time override:

NIX_CONFIG='accept-flake-config = true' nh os switch

After that rebuild, later cache changes need only j write-flake before the build. The setting accepts Nix configuration from every flake used on these hosts.

If the checkout lives outside ~/nix, set the Home Manager option dotfiles.checkoutPath. It controls build helpers and editable asset symlinks; the global justfile also accepts a DOTFILES_CHECKOUT_PATH override.

Enable the formatting pre-commit hook once per clone:

git config --local core.hooksPath .githooks

See AGENTS.md for detailed agent guidance, framework patterns, and MCP setup. See secrets/README.md for key provisioning and SOPS.