play

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

With no annotations provided, the description must disclose behavioral traits. It fails to mention side effects like overwriting the queue, account requirements (e.g., premium), or error conditions such as no active device. The description only lists parameters without behavioral context.

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 concise, front-loaded with the main action, and uses a structured bullet list for arguments. Every sentence adds value without redundancy.

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?

Despite having an output schema, the description lacks completeness for a playback tool with 5 parameters and no annotations. It does not cover edge cases like simultaneous context_uri and uris, or failure scenarios. It is adequate but has clear 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?

The schema coverage is 0%, so the description carries the burden of explaining parameters. It provides clear explanations for each parameter, including an example for uris. However, it does not explain constraints like mutual exclusivity between context_uri and uris or the dependency of offset_position on context_uri.

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 'Start or resume playback,' which is a specific verb+resource action. It 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 lacks explicit guidance on when to use this tool versus alternatives. It does not mention when not to use it, such as when playback is already active or when other tools like transfer_playback might be more appropriate.

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