nodered-mcp/README.md

nodered-mcp

A Python MCP server for Node-RED flow management, built on FastMCP and Pydantic.

Gives language models full read/write access to a Node-RED instance through the Admin HTTP API, with structured Pydantic responses, incremental flow patching, layout linting, and flexible authentication (token, basic, OAuth2).

Compared to node-red-mcp-server

This project was inspired by karavaev-evgeniy/node-red-mcp-server (TypeScript/npm). Key differences:

	node-red-mcp-server (TS)	nodered-mcp (Python)
Runtime	Node.js / npm	Python 3.11+ / uv
Framework	Custom MCP SDK	FastMCP
Responses	Raw JSON strings	Typed Pydantic models
Auth	Token only	Token, Basic, OAuth2
Deployment types	full only	full, nodes, flows, reload
Flow mutations	Replace entire flow	patch_flow with granular ops (add/remove/update/rewire)
Layout checks	None	lint_flow detects overlaps, spacing, wire crossings
Auto-lint	N/A	update_flow and patch_flow append warnings automatically
Tool count	19	22

Installation

Requires Python 3.11+ and uv:

git clone <repo-url> && cd nodered-mcp
uv sync

Quick Start

# Minimal — token auth (default)
export NODE_RED_URL=http://localhost:1880
export NODE_RED_TOKEN=your-api-token
uv run nodered-mcp

Configuration

All configuration is via environment variables with the NODE_RED_ prefix.

Variable	Default	Description
NODE_RED_URL	http://localhost:1880	Node-RED instance URL
NODE_RED_TOKEN	""	Bearer token (for token auth method)
NODE_RED_API_VERSION	v1	API version header
NODE_RED_AUTH_METHOD	token	Auth method: token, basic, or oauth
NODE_RED_AUTH_USERNAME	""	Username for basic or oauth auth
NODE_RED_AUTH_PASSWORD	""	Password/app password for basic or oauth auth
NODE_RED_OAUTH_TOKEN_URL	""	OAuth2 token endpoint URL
NODE_RED_OAUTH_CLIENT_ID	""	OAuth2 client ID

Authentication

Token (default)

Static bearer token sent with every request. This is the simplest method and matches how node-red-mcp-server works:

NODE_RED_URL=http://localhost:1880
NODE_RED_TOKEN=your-api-token

Basic Auth

HTTP Basic authentication, useful when Node-RED sits behind a forward auth proxy.

NODE_RED_AUTH_METHOD=basic
NODE_RED_AUTH_USERNAME=admin
NODE_RED_AUTH_PASSWORD=your-password

Basic Auth with Authentik

A common setup is Node-RED behind Authentik as a forward auth proxy. Authentik intercepts requests, validates credentials, and sets session cookies before forwarding to Node-RED.

1. Create an Authentik application for your Node-RED instance using the Forward Auth (single application) provider.

2. Configure your reverse proxy (Traefik, nginx, Caddy) to use Authentik's forward auth endpoint. For example, with Traefik:

   # docker-compose.yml (Traefik labels on the Node-RED service)
   labels:
     - "traefik.http.routers.nodered.middlewares=authentik@docker"
   

3. Create an Authentik service account (or use an existing user) and generate an app password under the user's token settings. This avoids MFA prompts that would block API access.

4. Configure nodered-mcp:

   NODE_RED_URL=https://nodered.yourdomain.com
   NODE_RED_AUTH_METHOD=basic
   NODE_RED_AUTH_USERNAME=service-account
   NODE_RED_AUTH_PASSWORD=the-app-password-from-authentik
   

The basic auth credentials are sent to Authentik's proxy, which validates them and sets cookies. Subsequent requests use the session cookie, so Node-RED itself doesn't need auth enabled.

OAuth2 Client Credentials

Fetches a short-lived JWT via OAuth2 client credentials grant. The token is cached and auto-refreshed with a 30-second expiry buffer. On a 401 response, the server retries once with a fresh token.

NODE_RED_AUTH_METHOD=oauth
NODE_RED_AUTH_USERNAME=service-account
NODE_RED_AUTH_PASSWORD=service-password
NODE_RED_OAUTH_TOKEN_URL=https://auth.example.com/application/o/token/
NODE_RED_OAUTH_CLIENT_ID=your-client-id

MCP Client Configuration

Claude Desktop

{
  "mcpServers": {
    "nodered": {
      "command": "uv",
      "args": ["--directory", "/path/to/nodered-mcp", "run", "nodered-mcp"],
      "env": {
        "NODE_RED_URL": "http://localhost:1880",
        "NODE_RED_TOKEN": "your-token"
      }
    }
  }
}

Claude Code

{
  "mcpServers": {
    "nodered": {
      "command": "uv",
      "args": ["--directory", "/path/to/nodered-mcp", "run", "nodered-mcp"],
      "env": {
        "NODE_RED_URL": "http://localhost:1880",
        "NODE_RED_TOKEN": "your-token"
      }
    }
  }
}

Tools

Flow Tools (12)

Tool	Description
get_flows	Get all flows with summary statistics
update_flows	Replace all flows with deployment type control (full/nodes/flows/reload)
get_flow	Get a single flow by ID
update_flow	Update a single flow (auto-lints after save)
list_tabs	List all flow tabs (workspaces)
create_flow	Create a new flow tab
delete_flow	Delete a flow tab
get_flows_state	Get runtime state (started/stopped)
set_flows_state	Start or stop the flow runtime
get_flows_formatted	Get flows grouped by tabs/nodes/subflows with statistics
visualize_flows	Markdown-formatted per-tab structural overview
patch_flow	Incremental operations: add_nodes, remove_nodes, update_node, rewire, set_label, set_info, set_disabled (auto-lints after save)

Node Tools (6)

Tool	Description
inject	Trigger an inject node
get_nodes	List installed node modules
get_node_info	Detailed info about a node module
toggle_node_module	Enable or disable a node module
find_nodes_by_type	Find all nodes of a given type
search_nodes	Search nodes by name or any property

Layout Tools (1)

Tool	Description
lint_flow	Check a flow for node overlaps, insufficient spacing, and wire-through-node crossings. Optionally scoped to specific node IDs.

Settings Tools (2)

Tool	Description
get_settings	Get Node-RED runtime settings
get_diagnostics	Get runtime diagnostics (Node.js version, OS, modules)

Utility Tools (1)

Tool	Description
api_help	Node-RED Admin API endpoint reference

Architecture

src/nodered_mcp/
├── server.py              # FastMCP server, config, client init
├── config.py              # Pydantic Settings (env vars)
├── client.py              # Async httpx wrapper with auth
├── models/
│   ├── base.py            # BaseApiModel with from_api()
│   ├── flow.py            # Node, FlowTab, Flow, FlowState
│   ├── node.py            # NodeModule, NodeSet
│   ├── responses.py       # FlowList, FlowSummary, Settings, etc.
│   └── layout.py          # LayoutIssue, LayoutReport
└── tools/
    ├── flows.py           # Flow CRUD + patch + auto-lint
    ├── nodes.py           # Node management + search
    ├── layout.py          # Layout lint checks
    ├── settings.py        # Settings + diagnostics
    └── utility.py         # API help reference

The layer diagram is simple:

MCP Tools (thin async functions, return Pydantic models)
  ↓
NodeRedClient (async httpx, returns raw dicts)
  ↓
Node-RED Admin HTTP API

Development

make all              # format + lint + test
make check            # lint + test (no format)
make test             # uv run pytest tests/ -v
make lint             # uv run ruff check src/ tests/
make format           # uv run ruff format src/ tests/

Run a single test file:

uv run pytest tests/tools/test_layout.py -v

Run with coverage:

uv run pytest tests/ -v --cov=src/nodered_mcp --cov-report=term-missing

Always use uv run — never bare python or pytest.

See conventions.md for detailed code patterns (model layering, tool conventions, client architecture).

License

MIT