mcp-arr-lite

Lightweight MCP server for Radarr and Sonarr with a small set of granular, purpose-built tools. Unofficial project.

Why this project?

General "arr" MCP servers (like Knuckles-Team/arr-mcp) auto-generate thousands of tools from the Arr API and hand the whole surface to the LLM. mcp-arr-lite is the opposite:

• Granular tools: exactly the operations needed for the "can you grab X for me?" flow — lookup, add, search releases, grab — no admin/config noise.

• Preferred-indexer logic: search tools default to the indexer with the lowest numeric priority, deterministic instead of prompt-dependent.

• HITL-friendly: read-only tools (lookup, list indexers) can be auto-approved; add/search/grab require explicit user approval.

• Dual transport: stdio (npx) and HTTP (Docker).

Comparison with Knuckles-Team/arr-mcp

Tools

Requirements

• Node.js >= 20 (npx) or Docker (container)

• Radarr and/or Sonarr with an API key

Installation

Docker Compose (recommended)

services:
  arr-mcp:
    image: ghcr.io/cuti27/mcp-arr-lite:latest
    restart: unless-stopped
    environment:
      - RADARR_URL=http://radarr:7878
      - RADARR_API_KEY=your-radarr-api-key
      - SONARR_URL=http://sonarr:8989
      - SONARR_API_KEY=your-sonarr-api-key
      - MCP_TRANSPORT=http
      - MCP_AUTH_TOKEN=your-secure-token-here
      - PORT=3000
      - HOST=0.0.0.0
      - LOG_LEVEL=info

Only configure the apps you use — Radarr and Sonarr are both optional at startup; tools for an unconfigured app will return an error.

stdio (npx)

RADARR_URL=http://radarr:7878 \
RADARR_API_KEY=... \
SONARR_URL=http://sonarr:8989 \
SONARR_API_KEY=... \
MCP_TRANSPORT=stdio \
npx -y @cuti27/mcp-arr-lite

Environment variables

See .env.example. Required per app: RADARR_URL + RADARR_API_KEY, SONARR_URL + SONARR_API_KEY. MCP_AUTH_TOKEN is required when MCP_TRANSPORT=http.

Security

• HTTP transport enforces bearer auth, rate limiting (60 req/min/IP) and a 1 MB body limit.

• API keys are redacted from logs.

• Only run the HTTP transport with MCP_AUTH_TOKEN set and behind a TLS-terminating reverse proxy.

License

MIT