AlejandroGomezFrieiro/noogle_mcp_server

Noogle Server

This project provides a tool for querying Nix built-in and Nixpkgs function documentation from noogle.dev. It leverages uv2nix for robust packaging and reproducible development environments.

Why write this?

The major reason to write it was to test for myself how much can I push an AI-assisted workflow using codecompanion inside my custom neovim configuration. I am not a web developer and, as part of my day-to-day job I also do not have to write any REST API. So I wanted to challenge myself to test uv2nix (which I always found and still kind of find difficult to use) and figure out what kind of things work and what does not work when doing AI-assisted development.

Features

• Nix Documentation Query: Uses the query_nix_docs tool to fetch and parse documentation from noogle.dev.
• Structured Output: Presents documentation in a clear Markdown format, including inputs, types, examples, and aliases.
• Pure Nix Development: Provides a pure development shell using uv2nix for consistent, reproducible environments with editable installs.
• Impure Development: Supports an impure development workflow for those who prefer managing their Python virtual environments with uv directly.

Usage

Standalone with Nix

The output of flake.nix contains a script to start the server. After cloning the repository, you can do

nix run .
nix run github:AlejandroGomezFrieiro/noogle_mcp_server

Standalone Python

The nix-docs-server is an application that exposes the query_nix_docs functionality as a service (via FastMCP). First install the server with

pip install noogle_mcp_server

Then start the server with

python -m noogle_mcp_server

Editor-integrated tool.

This tool can easily be setup as an mcp tool using, for example, mcphub.

Using nix (recommended)

{
    "mcp_servers": {
      "noogle_mcp_server": {  
        "args": [  
          "run",  
          "github:AlejandroGomezFrieiro/noogle_mcp_server"  
        ],  
        "command": "nix"  
      },
    }
}

Using Python

After installing it following the instructions, you can call it with

{
    "mcp_servers": {
      "noogle_mcp_server": {  
        "args": [  
          "-m",  
          "noogle_mcp_server"  
        ],  
        "command": "python"  
      },
    }
}

Development

This project offers two modes for setting up development environments using Nix: a pure Nix-managed environment leveraging uv2nix and an impure environment that uses uv directly.

Prerequisites

• Nix
  • Must also have flakes experimental feature setup.

Impure Development (nix develop .#impure)

This development shell sets up python312 and uv from Nixpkgs. It configures uv to use the Nix-provided Python interpreter and prevents it from downloading its own, while allowing you to manage your Python virtual environment (e.g., using uv venv) outside of Nix. This is suitable if you prefer a traditional uv-based workflow.

nix develop .#impure
# Inside the shell, you can use uv:
# uv venv
# source .venv/bin/activate

Pure Development (nix develop .#uv2nix or nix develop)

This shell provides a purely Nix-built virtual environment with your project's dependencies. It uses uv2nix to create an isolated, reproducible environment and enables "editable" installs for your local project files. This means changes to your source code are reflected immediately in the virtual environment without requiring a Nix rebuild.

nix develop .#uv2nix
# Or simply use the default shell:
nix develop

Once inside this shell, your local project files (e.g., noogle_mcp_server/) are installed in "editable" mode, allowing for immediate reflection of code changes.

This environment provides the benefits of Nix's reproducibility while maintaining a flexible development experience for Python projects.