Nix Module Generator

Scaffolds new Nix modules following this repository's architectural patterns.

Usage

Just describe what module you want to create:

• •"Create a new system module for audio-pro configuration"
• •"Add a darwin module for Rectangle window manager"
• •"Generate a home module for alacritty terminal"

The skill will:

1. •Ask clarifying questions if needed (module type, name, additional options)
2. •Generate the module file with standard structure
3. •Add the import to parent default.nix
4. •Verify the module follows repository patterns

Module Types

System Modules (system/<name>/)

• •Purpose: NixOS-specific system configuration
• •Namespace: config.modules.<name>
• •Examples: audio, networking, gnome, i3, minecraft-server
• •Typical contents: systemd services, system packages, kernel modules

Darwin Modules (darwin/<name>/)

• •Purpose: macOS-specific system configuration
• •Namespace: config.modules.<name>
• •Examples: aerospace, homebrew, system-defaults
• •Typical contents: LaunchAgents, system preferences, macOS-specific packages

Home Modules (home/<name>/)

• •Purpose: Cross-platform user environment configuration
• •Namespace: config.modules.<name>
• •Examples: git, neovim, tmux, zsh, ghostty
• •Typical contents: dotfiles, user packages, application configs

Standard Module Pattern

All modules follow this structure:

{ lib, config, pkgs, ... }:
with lib;
let
  cfg = config.modules.<name>;
in
{
  options.modules.<name> = {
    enable = mkEnableOption "Enable <name> configuration";
    # Additional options if needed (fonts, colors, ports, etc.)
  };

  config = mkIf cfg.enable {
    # Implementation goes here
  };
}

When to Add Additional Options

✅ DO add options for:

• •Configuration that varies per host (fonts, colors, display settings)
• •Feature flags within the module (enable-plugins, use-wayland)
• •Resource limits (memory, ports, timeouts)
• •Complex nested configuration (servers, profiles, themes)

❌ DON'T add options for:

• •Implementation details users shouldn't customize
• •Values that should be consistent across all hosts
• •Temporary configuration (use host overrides instead)

Best Practices

Module Organization

• •One feature per module (don't combine unrelated config)
• •Keep modules self-contained (minimal cross-module dependencies)
• •Use conditional config: mkIf cfg.enable { ... }

Cross-Module Dependencies

# BAD: Assumes another module is enabled
config = mkIf cfg.enable {
  xsession.windowManager.i3.config.startup = [ ... ];
};

# GOOD: Guard cross-module config
config = mkIf cfg.enable {
  xsession.windowManager.i3 = mkIf (config.xsession.windowManager.i3.enable or false) {
    config.startup = [ ... ];
  };
};

Importing Shared Constants

# Colors (Catppuccin palette)
let
  colors = import ../../common/colors.nix;
in {
  foreground = "${colors.text}";
  background = "${colors.base}";
}

# Fonts
let
  fonts = import ../../common/fonts { inherit pkgs; };
in {
  home.packages = fonts;
}

Examples

Simple Module (git)

{ lib, config, ... }:
with lib;
let cfg = config.modules.git;
in {
  options.modules.git = {
    enable = mkEnableOption "Enable git configuration";
  };

  config = mkIf cfg.enable {
    programs.git = {
      enable = true;
      userName = "Your Name";
      userEmail = "your@email.com";
    };
  };
}

Module with Options (ghostty)

{ lib, config, ... }:
with lib;
let cfg = config.modules.ghostty;
in {
  options.modules.ghostty = {
    enable = mkEnableOption "Enable ghostty configuration";

    fontFamily = mkOption {
      type = types.str;
      default = "AdwaitaMono Nerd Font";
      description = "Ghostty font family";
    };

    fontSize = mkOption {
      type = types.int;
      default = 11;
      description = "Ghostty font size";
    };
  };

  config = mkIf cfg.enable {
    programs.ghostty = {
      enable = true;
      settings = {
        font-family = cfg.fontFamily;
        font-size = cfg.fontSize;
      };
    };
  };
}

Complex Module (minecraft-server)

{ lib, config, pkgs, inputs, ... }:
with lib;
let cfg = config.modules.minecraft-server;
in {
  imports = [ inputs.nix-minecraft.nixosModules.minecraft-servers ];

  options.modules.minecraft-server = {
    enable = mkEnableOption "Enable Minecraft server configuration";

    servers = mkOption {
      type = types.attrsOf (types.submodule {
        options = {
          jvmOpts = mkOption {
            type = types.nullOr types.str;
            default = null;
          };
          serverProperties = mkOption {
            type = types.attrsOf (types.oneOf [ types.bool types.int types.str ]);
            default = {};
          };
        };
      });
      default = {};
    };
  };

  config = mkIf cfg.enable {
    nixpkgs.overlays = [ inputs.nix-minecraft.overlay ];
    services.minecraft-servers = {
      enable = true;
      # Server configuration...
    };
  };
}

Workflow

When you invoke this skill, it will:

1. •

   Clarify requirements

   • •Ask for module type (system/darwin/home) if not specified
   • •Ask for module name (kebab-case preferred)
   • •Ask if additional options needed beyond enable
2. •

   Generate module file

   • •Create <type>/<name>/default.nix
   • •Follow standard pattern
   • •Include helpful comments
3. •

   Update parent imports

   • •Add ./<name> to <type>/default.nix imports
   • •Maintain alphabetical order
4. •

   Provide next steps

   • •How to enable the module in host config
   • •Where to add implementation details
   • •Examples of similar modules to reference

After Generation

Enable in Host Config

# hosts/<hostname>/default.nix
modules = {
  <name>.enable = true;  # For system/darwin modules
};

# OR for home modules:
home-manager.users.andrew = {
  modules = {
    <name>.enable = true;
  };
};

Test the Module

# For NixOS
sudo nixos-rebuild build --flake .#<hostname>

# For Darwin
darwin-rebuild build --flake .

# Check for errors, then switch
sudo nixos-rebuild switch --flake .#<hostname>
# or
sudo darwin-rebuild switch --flake .

Troubleshooting

"Infinite recursion encountered"

• •Usually from circular module dependencies
• •Check for config.modules.X references in let bindings
• •Use mkIf guards properly

"The option modules.<name> does not exist"

• •Module not imported in parent default.nix
• •Check spelling matches between file and option name

"Attribute already exists"

• •Another module setting same config
• •Use mkMerge or mkOverride to combine

Related Documentation

• •CLAUDE.md - Repository architecture overview
• •Module pattern - See any existing module for reference
• •Common directory - Shared constants (colors, fonts, nix settings)