music_now_playing

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

No annotations are provided, so the description carries the whole burden, and it delivers only the enumerated state values (playing, paused, stopped). It says nothing about whether the app must be running, whether the call launches Music, permission requirements, or what happens when nothing is playing — and the text truncates before covering more.

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?

The opening is well front-loaded with the core purpose, but the description is truncated mid-sentence ('the current track (id...'), leaving a dangling parenthetical and an unfinished thought. An incomplete definition cannot be called well-structured.

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 no annotations and no output schema, the description is the only source of information about return shape and behavior, and it fails to deliver because it is cut off. Key facts an agent needs — what fields come back, behavior when stopped, whether Music must be open — are absent.

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 zero parameters, so there is nothing for the description to disambiguate. The baseline of 4 applies; no parameter explanation is needed.

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 specific verb and resource: reporting what the Music app is playing, with player state and current track identified. That distinguishes it reasonably from siblings like music_playback (which controls playback) and music_search_library, though the sentence is cut off before it finishes describing the payload.

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 when-to-use or when-not-to-use guidance and no reference to any alternative tool. An agent must infer that this is the read-side counterpart of music_playback entirely on its own.

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