playMusic

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

No annotations exist, so the description must disclose side effects, requirements (like active device), and behavior such as replacing current queue. It only states the action, leaving the agent to guess about deviceId handling, error conditions, or return values.

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, to-the-point sentence. It's efficient but lacks additional context that could aid selection; still, it doesn't waste 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?

With no output schema and no annotations, the description fails to convey essential behavioral details such as whether playback starts immediately, what happens without a deviceId, or the response format. Incomplete for a 4-param tool with optional interactions.

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?

All four parameters are fully described in the schema, so the description adds no additional parameter semantics. It doesn't explain how id, uri, and type interrelate or which takes precedence.

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 uses a specific verb ('Start playing') and resource ('Spotify track, album, artist, or playlist'), clearly distinguishing from sibling playback controls like pause and skip. It accurately reflects the tool's function.

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?

No explicit when-to-use or alternative guidance is provided. While the function is intuitive, it doesn't mention exclusions (e.g., when to use resume vs play) or prerequisites.

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