mcp-nix 0.4.0

MCP server for Nixpkgs, NixOS and Home Manager

A complete MCP server for Nix*

Features

• Search Nixpkgs and read package derivations
• Broad options coverage
  • NixOS
  • Home Manager
  • Nix Darwin
  • Other: Nixvim Impermanence, MicroVM.nix, nix-nomad, simple-nixos-mailserver, sops-nix, nixos-hardware, disko.
• Search the nix standard library and read function definitions
• Find versions of nixpkgs in which a package exists

Installation

Use the following configuration to add the MCP server to your client:

Using uvx:

{
  "mcpServers": {
    "nix": {
      "command": "uvx",
      "args": ["mcp-nix"]
    }
  }
}

Using nix run:

{
  "mcpServers": {
    "nix": {
      "command": "nix",
      "args": ["run", "github:felixdorn/mcp-nix"]
    }
  }
}

Declaratively:

Add the flake input:

{
  inputs.mcp-nix.url = "github:felixdorn/mcp-nix";
}

Then reference the package:

{
  command = "${inputs.mcp-nix.packages.${system}.default}/bin/mcp-nix";
}

Tools

Tool	Description
search_nixpkgs	Search Nixpkgs packages
read_derivation	Read package source code
search_options	Search options for many projects
list_versions	List available versions for a project
show_option_details	Get option details or list children
read_option_declaration	Read option source code
find_nixpkgs_commit_with_package_version	Get nixpkgs commit for a version, shows available versions if not found (NixHub)
search_nix_stdlib	Search Nix stdlib functions (Noogle)
help_for_stdlib_function	Get help for a stdlib function (Noogle)

Excluding Tools

Use --exclude to disable specific tools:

{
  "mcpServers": {
    "nix": {
      "command": "uvx",
      "args": ["mcp-nix", "--exclude=read_derivation,read_option_declaration"]
    }
  }
}

Contributing

Read CONTRIBUTING.md

Acknowledgments

Thanks to the NixOS Search Team, ExtraNix, NüschtOS, nix-nomad, NixHub, Noogle for maintaining the backends and pipeline this server uses and for the Nix community for making any of this possible.

License

GPLv3: License

<!-- mcp-name: io.github.felixdorn/mcp-nix -->