nwtools-mcp

An MCP server that gives LLMs accurate IPv4 subnet and address tools. LLMs are unreliable at network math — this server provides deterministic, correct results via Python's ipaddress standard library.

PyPI: https://pypi.org/project/nwtools-mcp/

Tools

Environment variables

Local use (stdio)

The stdio transport is used when Claude Desktop spawns the server as a subprocess. No network port is opened.

Run from PyPI with uvx

The simplest way to run the server locally is:

uvx nwtools-mcp

That runs the nwtools-mcp console command from an isolated ephemeral environment. For a persistent install:

uv tool install nwtools-mcp
nwtools-mcp

Install and run directly:

pip install -e .
python main.py

Or use the console script:

nwtools-mcp

Or install from PyPI with pip:

pip install nwtools-mcp
nwtools-mcp

Or via Docker:

docker run --rm -i nwtools-mcp

Claude Desktop config

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "nwtools": {
      "command": "python",
      "args": ["/path/to/nwtools-mcp/main.py"]
    }
  }
}

Or run it directly from PyPI with uvx:

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

If you prefer a persistent uv-managed install, use:

{
  "mcpServers": {
    "nwtools": {
      "command": "nwtools-mcp"
    }
  }
}

Remote deployment (HTTP)

The server supports streamable-http (recommended) and sse transports for remote access. Set MCP_TRANSPORT to switch modes.

Running the HTTP server

# Local test
MCP_TRANSPORT=streamable-http python main.py

# With auth
API_KEY=your-secret MCP_TRANSPORT=streamable-http python main.py

With Docker:

docker build -t nwtools-mcp .
docker run --rm -p 8000:8000 \
  -e MCP_TRANSPORT=streamable-http \
  -e API_KEY=your-secret \
  nwtools-mcp

Operational endpoints

When running in HTTP mode, the container exposes two unauthenticated probe endpoints:

HTTP requests are also logged as structured JSON lines, including method, path, status, duration, client IP, and request ID.

TLS and auth

The server does not terminate TLS. In production, place it behind a reverse proxy. Example Caddy config:

nwtools.example.com {
    reverse_proxy localhost:8000
}

The built-in API_KEY check adds a layer of defense at the application level, but it does not replace TLS — never expose the server without it.

Connecting Claude to a remote server

In Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "nwtools": {
      "url": "https://nwtools.example.com/mcp",
      "headers": {
        "X-API-Key": "your-secret"
      }
    }
  }
}

On claude.ai, add the server under Settings → Integrations using the same URL.

Development

Install with the test extra and run the suite:

pip install -e ".[test]"
pytest

To build distribution artifacts locally:

uv build

Or with the standard Python build frontend:

pip install build
python -m build

Release

The project is now structured to publish cleanly to PyPI and run via uvx.

Build locally:

uv build

Publish manually:

uv publish

Automated publishing uses publish.yml with PyPI Trusted Publishing.

Release checklist:

1. Update version in pyproject.toml and __version__ in src/nwtools_mcp/__init__.py.
2. Run pytest.
3. Run uv build.
4. Commit and push to main.
5. Push a version tag such as v0.2.0.

Trusted Publisher settings:

• Create a pypi environment in the GitHub repository settings.
• Add a Trusted Publisher for this project on PyPI that matches:

Repository owner: crims0n Repository name: nwtools-mcp Workflow filename: publish.yml Environment name: pypi

The publish workflow builds the wheel and sdist, smoke-tests both artifacts, and then runs uv publish.

Requirements

• Python 3.11+
• mcp
• uvicorn