NetBox MCP Server

A small Model Context Protocol (MCP) server built with FastMCP that provides an interface to a NetBox instance.

This repository exposes NetBox resources (sites, site-groups, devices, etc.) as MCP tools and runs a streaming HTTP transport so clients can connect and receive streamed responses from the MCP server.

Architecture (FastMCP + streaming HTTP)

• FastMCP: The MCP tool registry and runtime. Tools are defined in app.py and decorated with @mcp.tool.
• NetBoxClient: a tiny async helper in app.py that wraps httpx.AsyncClient to call the NetBox API.
• Streaming HTTP transport: the MCP server is started with mcp.run(transport="http", ...) which runs an HTTP server that supports a streaming/chunked response transport. This is useful for clients that want to consume events or long-running responses incrementally rather than waiting for the entire result.

Conceptually the flow is:

1. Client connects to the FastMCP streaming HTTP endpoint.
2. Client requests a tool (for example, search_sites or get_site_group_details).
3. FastMCP calls the associated Python function in app.py, which may in turn call NetBox via NetBoxClient.
4. The result is streamed back over the HTTP transport as it becomes available.

Note: The low-level HTTP path/shape is provided by the FastMCP runtime. Clients that wish to connect should use a compatible MCP client or an HTTP client that supports reading chunked / streaming responses.

Environment variables

Set these before running the server:

• NETBOX_URL - Base URL to your NetBox instance (default: https://netbox.example.com).
• NETBOX_TOKEN - NetBox API token with read permissions.
• MCP_PORT - Port for the FastMCP HTTP transport. Defaults to 8000 if not set. If the value is not a valid integer, the server will exit with an error.

Example (macOS / zsh):

export NETBOX_URL="https://netbox.example.com"
export NETBOX_TOKEN="0123456789abcdef0123456789abcdef01234567"
export MCP_PORT=8000

Run the server

Start the MCP server with Python:

python3 app.py

The server will bind to 0.0.0.0 on the configured port and serve the FastMCP HTTP transport.

Tools included

app.py registers MCP tools for NetBox resources. Examples included in this repository:

• search_sites — search of dcim/sites/ (supports partial/case-insensitive name queries)
• get_site_details — site lookup
• search_site_groups — search of dcim/site-groups/ (supports name__ic)
• get_site_group_details — single site-group lookup by id

You can add more tools following the repository conventions: each NetBox resource has a search_ and get__details tool.

Verifying / testing

• Quick syntax check:

python3 -m py_compile app.py

• Start the server and use an HTTP client that supports streaming (for example, curl --no-buffer or a custom MCP client) to connect to the FastMCP HTTP transport and invoke tools.