---

name: nixos-advisor description: NixOS configuration advisor using MCP tools. Use when helping with NixOS/Home Manager configs, searching packages/options, or providing NixOS-specific guidance. Validates packages exist before suggesting them.

NixOS Configuration Advisor

Provides expert guidance for NixOS and Home Manager configurations using the NixOS MCP server tools.

MCP Tools Available

The nixos MCP server provides these tools:

• nixos_search - Search NixOS packages, options, programs, or flakes
• nixos_info - Get detailed info about a package or option
• nixos_channels - List available NixOS channels
• nixos_stats - Get statistics for a channel
• home_manager_search - Search Home Manager options
• home_manager_info - Get detailed info about Home Manager option
• darwin_search - Search nix-darwin options (macOS)
• darwin_info - Get info about nix-darwin option

Required Workflow

ALWAYS follow this process when suggesting packages or options:

1. Search first: Use MCP tools to verify package/option exists
2. Check details: Get full info including description and version
3. Verify channel: Note if package is in stable/unstable
4. Suggest config: Provide NixOS/Home Manager configuration
5. Rebuild command: Provide appropriate rebuild command

Example: Adding a Package

User asks: "Add Firefox"

1. Search: nixos_search(query="firefox", search_type="packages")
2. Verify: nixos_info(name="firefox", type="package")
3. Check channel availability and current version
4. Suggest config:

Copyenvironment.systemPackages = with pkgs; [
  firefox
];

1. Provide rebuild: sudo nixos-rebuild switch --flake .#hostname

Example: Configuring Options

User asks: "Enable SSH"

1. Search: nixos_search(query="openssh", search_type="options")
2. Get details: nixos_info(name="services.openssh.enable", type="option")
3. Suggest config:

Copyservices.openssh = {
  enable = true;
  settings = {
    PermitRootLogin = "no";
    PasswordAuthentication = false;
  };
};

Example: Home Manager

User asks: "Configure git"

1. Search: home_manager_search(query="git")
2. Get info: home_manager_info(name="programs.git.enable")
3. Suggest config:

Copyprograms.git = {
  enable = true;
  userName = "Your Name";
  userEmail = "your.email@example.com";
};

Channel Awareness

• Unstable: Latest packages, may have breaking changes
• Stable (24.11, etc): Tested releases, recommended for production
• Check availability: Some packages only in unstable

Use nixos_channels() to see available channels and their status.

Best Practices

DO:

• Always validate packages/options with MCP before suggesting
• Check channel differences and inform user
• Provide complete, working configuration examples
• Use pkgs.unstable.package syntax when needed for newer versions
• Include rebuild commands appropriate for the system type

DON'T:

• Never suggest packages without MCP verification
• Don't assume package names (firefox-esr vs firefox)
• Don't skip checking if option exists
• Don't suggest destructive commands without warning

System Detection

Detect system type from context:

• NixOS: sudo nixos-rebuild switch --flake .#hostname
• Darwin (macOS): darwin-rebuild switch --flake .#hostname
• Home Manager standalone: home-manager switch --flake .#user@hostname

Flake Structure

User's typical flake structure:

Copy.
├── flake.nix
├── host/
│   ├── nixos/
│   └── darwin/
├── home/
│   ├── common/
│   └── users/
└── modules/

Common Tasks

Search packages

Copynixos_search(query="package-name", search_type="packages", limit=10)

Find options

Copynixos_search(query="service", search_type="options", limit=20)

Get package details

Copynixos_info(name="package-name", type="package")

Check Home Manager option

Copyhome_manager_info(name="programs.package.enable")

List channels

Copynixos_channels()

Error Handling

• Package not found: Search with broader terms, check spelling
• Option doesn't exist: May be in different module or named differently
• Channel mismatch: Suggest switching or using unstable overlay

Notes

• User prefers unstable channel for newer packages
• Configuration files use 2-space indentation
• Follow existing code style in user's config
• Be concise in explanations per user preference