MCP-NixOS

★ 738

from utensils

A server for searching NixOS, Home Manager, and nix-darwin resources.

🔥🔥🔥🔥✓ VerifiedFreeNeeds API keys

#devops #git

MCP-NixOS - Because Your AI Shouldn't Hallucinate Package Names

What Is This?

An MCP server providing accurate, real-time information about:

NixOS packages - 130K+ packages that actually exist
NixOS options - 23K+ ways to configure your system
Home Manager - 5K+ options for dotfile enthusiasts
nix-darwin - 1K+ macOS settings Apple doesn't document
Nixvim - 5K+ options for Neovim configuration via NuschtOS search
FlakeHub - 600+ flakes from FlakeHub.com registry
Noogle - 2K+ Nix functions with type signatures via noogle.dev
NixOS Wiki - Community documentation and guides from wiki.nixos.org
nix.dev - Official Nix tutorials and guides from nix.dev
Package versions - Historical versions with commit hashes via NixHub.io
Binary cache status - Check if packages are cached on cache.nixos.org with download sizes
Local flake inputs - Explore your pinned flake dependencies directly from the Nix store (requires Nix)

The Tools

Just two. We consolidated 17 tools into 2 because your AI's context window isn't infinite.

~1,030 tokens total. That's it. While other MCP servers are hogging your context like it's Black Friday, we're sipping minimalist tea in the corner. Your AI gets NixOS superpowers without the bloat.

`nix` - Unified Query Tool

One tool to rule them all:

Copy & paste — that's it

nix(action, query, source, type, channel, limit)

Action What it does search Search packages, options, programs, or flakes info Get detailed info about a package or option stats Get counts and categories options Browse Home Manager/Darwin options by prefix channels List available NixOS channels flake-inputs Explore local flake inputs from Nix store cache Check binary cache status for packages

Source What it queries nixos Packages, options, programs home-manager Home Manager options darwin nix-darwin options flakes Community flakes (search.nixos.org) flakehub FlakeHub registry (flakehub.com) nixvim Nixvim Neovim configuration options noogle Nix function signatures and docs (noogle.dev) wiki NixOS Wiki articles (wiki.nixos.org) nix-dev Official Nix documentation (nix.dev) nixhub Package metadata and store paths (nixhub.io)

Examples:

Copy & paste — that's it

# Search NixOS packages
nix(action="search", query="firefox", source="nixos", type="packages")

# Get package info
nix(action="info", query="firefox", source="nixos", type="package")

# Search Home Manager options
nix(action="search", query="git", source="home-manager")

# Browse darwin options
nix(action="options", source="darwin", query="system.defaults")

# Search Nixvim options
nix(action="search", query="telescope", source="nixvim")

# Get Nixvim option info
nix(action="info", query="plugins.telescope.enable", source="nixvim")

# Search FlakeHub
nix(action="search", query="nixpkgs", source="flakehub")

# Get FlakeHub flake info
nix(action="info", query="NixOS/nixpkgs", source="flakehub")

# Search Noogle for Nix functions
nix(action="search", query="mapAttrs", source="noogle")

# Get Noogle function info
nix(action="info", query="lib.attrsets.mapAttrs", source="noogle")

# Browse Noogle function categories
nix(action="options", source="noogle", query="lib.strings")

# Search NixOS Wiki
nix(action="search", query="nvidia", source="wiki")

# Get Wiki page info
nix(action="info", query="Flakes", source="wiki")

# Search nix.dev documentation
nix(action="search", query="packaging tutorial", source="nix-dev")

# Search NixHub for package metadata
nix(action="search", query="nodejs", source="nixhub")

# Get detailed package info from NixHub (license, homepage, store paths)
nix(action="info", query="python", source="nixhub")

# Check binary cache status
nix(action="cache", query="hello")

# Check cache for specific version
nix(action="cache", query="python", version="3.12.0")

# Check cache for specific system
nix(action="cache", query="firefox", system="x86_64-linux")

# Get stats
nix(action="stats", source="nixos", channel="stable")

# List local flake inputs (requires Nix)
nix(action="flake-inputs", type="list")

# Browse files in a flake input
nix(action="flake-inputs", type="ls", query="nixpkgs:pkgs/by-name")

# Read a file from a flake input
nix(action="flake-inputs", type="read", query="nixpkgs:flake.nix")

`nix_versions` - Package Version History

Find historical versions with nixpkgs commit hashes. Output includes:

Package metadata (license, homepage, programs) when available
Platform availability per version (Linux/macOS)
Nixpkgs commit hash for reproducible builds
Attribute path for Nix expressions

Copy & paste — that's it

nix_versions(package, version, limit)

Examples:

Copy & paste — that's it

# List recent versions with metadata
nix_versions(package="python", limit=5)

# Find specific version
nix_versions(package="nodejs", version="20.0.0")

Development

Copy & paste — that's it

nix develop # Enter dev shell
nix build # Build package
pytest tests/ # Run tests
ruff check . # Lint
ruff format . # Format
mypy mcp_nixos/ # Type check

Acknowledgments

NixHub.io - Package version history
search.nixos.org - Official NixOS search
FlakeHub - Flake registry by Determinate Systems
Jetify - Creators of Devbox and NixHub
Noogle - Nix function search engine
NuschtOS - Static option search infrastructure powering Nixvim support
Nixvim - Neovim configuration framework for Nix

License

MIT - Because sharing is caring.

Created by James Brink. Maintained by mass̶o̶c̶h̶i̶s̶t̶s̶ enthusiasts who enjoy Nix.

Copy & paste — that's it

# Run directly (no install)
uvx mcp-nixos

# Or install
pip install mcp-nixos

Quick Start

🚨 No Nix/NixOS Required! Works on any system - Windows, macOS, Linux. You're just querying APIs.

Option 1: uvx (Recommended)

Copy & paste — that's it

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

Option 2: Nix

Copy & paste — that's it

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

Option 3: Docker

Copy & paste — that's it

{
 "mcpServers": {
 "nixos": {
 "command": "docker",
 "args": ["run", "--rm", "-i", "ghcr.io/utensils/mcp-nixos"]
 }
 }
}

Your AI now has access to real NixOS data instead of making things up. You're welcome.

Option 4: HTTP (Remote MCP)

FastMCP supports running this server over HTTP at a URL (the MCP endpoint defaults to /mcp).

Copy & paste — that's it

# Run an HTTP MCP server at http://127.0.0.1:8000/mcp
MCP_NIXOS_TRANSPORT=http MCP_NIXOS_HOST=127.0.0.1 MCP_NIXOS_PORT=8000 mcp-nixos

STDIO (default):

Copy & paste — that's it

MCP_NIXOS_TRANSPORT=stdio mcp-nixos

Custom path:

Copy & paste — that's it

MCP_NIXOS_TRANSPORT=http MCP_NIXOS_PATH=/api/mcp mcp-nixos

Stateless HTTP (disables per-client session state):

Copy & paste — that's it

MCP_NIXOS_TRANSPORT=http MCP_NIXOS_STATELESS_HTTP=1 mcp-nixos

Option 5: Pi Coding Agent

Pi does not speak MCP natively. Two supported paths:

A. pi-mcp-adapter (recommended — speaks MCP, single source of truth):

Copy & paste — that's it

pi install npm:pi-mcp-adapter

Then add to ~/.pi/agent/mcp.json:

Copy & paste — that's it

{
 "mcpServers": {
 "nixos": {
 "command": "uvx",
 "args": ["mcp-nixos"],
 "lifecycle": "lazy"
 }
 }
}

B. Project-local extension (clone + run): this repo ships .pi/extensions/mcp-nixos.ts, auto-loaded when you run pi in the cloned repo. Optional: cd .pi && npm install for editor type resolution. Pi runs it either way.

Installation

You DON'T need Nix installed. This runs anywhere Python runs.

Copy & paste — that's it

# Run directly (no install)
uvx mcp-nixos

# Or install
pip install mcp-nixos

For Nix users:

Copy & paste — that's it

nix run github:utensils/mcp-nixos
nix profile install github:utensils/mcp-nixos

Declarative Installation (NixOS / Home Manager / nix-darwin)

mcp-nixos is available in nixpkgs:

Copy & paste — that's it

# NixOS (configuration.nix)
environment.systemPackages = [ pkgs.mcp-nixos ];

# Home Manager (home.nix)
home.packages = [ pkgs.mcp-nixos ];

# nix-darwin (darwin-configuration.nix)
environment.systemPackages = [ pkgs.mcp-nixos ];

Or use the flake directly with the provided overlay:

Copy & paste — that's it

# flake.nix
{
 inputs = {
 nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 mcp-nixos.url = "github:utensils/mcp-nixos";
 };

 outputs = { self, nixpkgs, mcp-nixos, ... }: {
 # Example: NixOS configuration
 nixosConfigurations.myhost = nixpkgs.lib.nixosSystem {
 system = "x86_64-linux";
 modules = [{
 nixpkgs.overlays = [ mcp-nixos.overlays.default ];
 environment.systemPackages = [ pkgs.mcp-nixos ];
 }];
 };

 # Example: Home Manager standalone
 homeConfigurations.myuser = home-manager.lib.homeManagerConfiguration {
 pkgs = import nixpkgs {
 system = "x86_64-linux";
 overlays = [ mcp-nixos.overlays.default ];
 };
 modules = [{
 home.packages = [ pkgs.mcp-nixos ];
 }];
 };
 };
}

MCP-NixOS - Because Your AI Shouldn't Hallucinate Package Names

What Is This?

The Tools

nix - Unified Query Tool

nix_versions - Package Version History

Development

Acknowledgments

License

Quick Start

Option 1: uvx (Recommended)

Option 2: Nix

Option 3: Docker

Option 4: HTTP (Remote MCP)

Option 5: Pi Coding Agent

Installation

Declarative Installation (NixOS / Home Manager / nix-darwin)

`nix` - Unified Query Tool

`nix_versions` - Package Version History