play

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

With no annotations provided, the description carries the burden of behavioral disclosure. It explains the main behavior (start/resume) and the no-URI fallback, which is useful. However, it does not mention device-related failure modes, authorization requirements, or what happens if no active device is available, leaving some behavioral ambiguity.

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 description is two sentences, front-loaded with the core action, and contains no redundant or filler text. Every sentence contributes a meaningful behavioral detail.

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?

For a simple player control tool with no output schema and well-documented parameters, the description covers the essential behaviors and common use cases. It could add more about device handling or edge cases, but the schema and sibling context mitigate those gaps.

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?

Schema description coverage is 100%, so the schema already documents all five parameters. The description adds minimal parameter-level meaning beyond restating that URIs can be tracks, albums, artists, or playlists. It does not significantly enhance the schema-provided semantics.

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?

The description clearly states the tool's function with a specific verb ('Start or resume playback') and identifies the resource types it can play (track, album, artist, playlist URI). It also distinguishes itself from sibling tools like pause, next_track, and previous_track by focusing on starting or resuming playback.

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?

The description provides clear usage context: play specific URIs or resume playback if no URI is provided. It does not explicitly name alternatives or exclusion conditions, but the behavior is obvious enough given the sibling tools and the explicit resume behavior.

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