Play music

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

Without annotations, the description carries full burden. It discloses that the tool searches for the best match and starts playback, and that it reports what was picked. This is sufficient, though details like whether playback resumes or replaces current are omitted.

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 three sentences, front-loaded with the core action, includes illustrative examples, and ends with a practical instruction. No unnecessary words.

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?

Given 4 parameters and no output schema, the description covers the two usage modes, provides examples, and mentions reporting. It does not elaborate on device_id, but the reference to the devices tool suffices. Overall, it is complete enough for an agent.

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?

With 100% schema coverage, baseline is 3. The description adds value by explaining that query is a free-text search, type optional, and uri alternative. It also indicates that the tool reports its choice, which is useful for understanding return behavior.

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 purpose: 'Plays music by free-text query (searches and starts the best match) or by Spotify URI.' It distinguishes from siblings like search or queue by focusing on immediate playback and handling multiple input styles.

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 concrete examples of when to use the tool ('play some Radiohead', 'play the album Kind of Blue') and instructs the agent to relay the result to the user. However, it does not explicitly exclude cases or mention alternative tools.

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