jellyfin_now_playing

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

No annotations are provided, so the description carries the full burden. It usefully discloses that this is a live point-in-time snapshot ("right now") covering active sessions and their devices, but says nothing about authentication needs against the Jellyfin server, whether inactive/paused sessions are included, or any rate considerations.

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

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

A single short sentence that front-loads the subject (who is watching) and appends the returned attribute (device). No filler, no restatement of the tool name.

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

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

With zero parameters and an output schema present, the description does not need to explain return values, and it correctly stays brief. The remaining gap is environmental context (which Jellyfin instance/connection it queries), which is minor for a simple status read.

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

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

The tool takes no parameters, so there is nothing for the description to disambiguate. Baseline of 4 applies for a zero-argument tool.

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

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

States a concrete verb ("Show") and a concrete resource ("who is watching on Jellyfin right now"), plus the returned detail (device). The only sibling tools are arr_* integrations, so there is no competing Jellyfin tool to distinguish from, but the description also doesn't scope itself against any other session/status query.

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

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

There is no explicit when-to-use or when-not-to-use guidance and no named alternative. For a zero-parameter, read-only snapshot tool the invocation context is largely self-evident from the name and description, which lands it at implied usage rather than explicit routing.

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