mcp-arr-lite

radarr_grab

Starts downloading a movie release in Radarr after user confirmation, using a release GUID from search results.

Instructions

Start downloading a movie release in Radarr. Requires user confirmation before calling.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "guid": "<guid>"
    },
    "name": "radarr_grab"
  }
}

Input Schema

Name	Required	Description	Default
`guid`	Yes	Release guid (from radarr_search_releases)
`indexerId`	No	Indexer id that produced the release

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 18, 2026

TDQS

B3.4/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description must disclose behavioral traits. It correctly indicates this is a destructive/mutating action (downloading), which is essential. However, it doesn't specify if the tool is idempotent, what happens on duplicates, or if it sends the download to a connected client. The user confirmation requirement is helpful but leaves gaps about side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two concise sentences with no wasted words. It front-loads the primary purpose and adds the critical requirement (user confirmation) in the second sentence. Could be slightly improved by removing the redundant 'before calling' given the tool name implies execution.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has a simple input schema (2 parameters, no nested objects, no output schema), the description is adequate but not thorough. It lacks details about the workflow (e.g., requiring prior search), return behavior, or error states. For a potentially destructive action, more completeness would be beneficial.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds no additional parameter information beyond the schema. The 'guid' parameter is documented as coming from radarr_search_releases, which is useful context implied by the description but not explicitly linked to the parameter. The description does not compensate for the lack of nested objects or enums.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly uses the verb 'start downloading' with the resource 'movie release in Radarr', establishing a specific action. It distinguishes from sibling tools like radarr_search_releases (search only) and radarr_add (add movie to library). The purpose is well-defined but could explicitly mention it's the final step to initiate a download.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states 'Requires user confirmation before calling', which sets a clear prerequisite about human approval. However, it doesn't say when to use this vs. alternatives like sonarr_grab (for TV series), nor does it describe the typical workflow (e.g., first search, then grab). The guidance is minimal but not misleading.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server