MCP MCP Server

MCP server for Nixpkgs, NixOS and Home Manager

Local serverstdio

What is the MCP MCP server?

MCP MCP server is a locally run integration for AI assistants that speak the Model Context Protocol. MCP server for Nixpkgs, NixOS and Home Manager.

What you get

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

  • Search Nixpkgs and read package derivations —
  • Broad options coverage —
  • simple-nixos-mailserver
  • nixos-hardware
  • Search the nix standard library and read function definitions —
  • Find versions of nixpkgs in which a package exists —

Setting it up

Setup follows the usual MCP pattern — install or clone the server, register it in your client's configuration file, restart the client. The configuration blocks on this page cover the common clients.

What the assistant can call

Once MCP is connected, these are the calls the assistant has available:

  • 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)
  • Tools — The Tools tool exposed by this server
  • Contributing — The Contributing tool exposed by this server
  • Acknowledgments — The Acknowledgments tool exposed by this server

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • With 12 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch MCP.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the mcp mcp server does with a few real requests.

Choosing this one

Plenty of developer tooling servers cover similar ground. The differences that matter in practice are scope of access and how much setup stands between you and a working tool call. MCP's toolset — search_nixpkgs, read_derivation, search_options and 9 more — is a fair guide to whether it matches your workflow.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Available tools

ToolWhat it does
search_nixpkgsSearch Nixpkgs packages
read_derivationRead package source code
search_optionsSearch options for many projects
list_versionsList available versions for a project
show_option_detailsGet option details or list children
read_option_declarationRead option source code
find_nixpkgs_commit_with_package_versionGet nixpkgs commit for a version, shows available versions if not found (NixHub)
search_nix_stdlibSearch Nix stdlib functions (Noogle)
help_for_stdlib_functionGet help for a stdlib function (Noogle)
ToolsThe Tools tool exposed by this server.
ContributingThe Contributing tool exposed by this server.
AcknowledgmentsThe Acknowledgments tool exposed by this server.

How to install the MCP MCP server

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

Configuration as documented by the project. Restart the client after saving.

Example prompts to try

  • Use MCP to search nixpkgs.
  • Use MCP to read derivation.
  • Use MCP to search options.

Frequently asked questions

It connects MCP to MCP-compatible AI assistants such as Claude and Cursor, exposing 12 tools (search_nixpkgs, read_derivation, search_options, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with MCP directly.