play

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action ('Start playback') and describes the return format, but lacks details about potential side effects, error conditions, authentication requirements, or rate limits. The return description adds some value, but more behavioral context would be needed for a higher score.

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 well-structured with clear sections (purpose, args, returns) and uses minimal sentences that each serve a distinct purpose. The main statement is front-loaded, though the formatting with separate sections could be slightly more integrated for optimal conciseness.

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 no annotations, no output schema, and a single parameter with 0% schema coverage, the description provides basic purpose, parameter semantics, and return format. However, for a playback control tool that likely interacts with physical devices, more context about error handling, device availability, or state dependencies would improve completeness.

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 0% schema description coverage for the single parameter, the description fully compensates by explaining the 'name' parameter's purpose and default behavior ('If None, uses the current device'). This adds meaningful semantic context beyond what the bare schema provides, though it doesn't cover all possible edge cases or validation rules.

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 action ('Start playback') and target resource ('on a Sonos device'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from similar playback-related siblings like 'play_index' or 'resume' (if present), which would require more specific scope definition for a perfect score.

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 implies usage when starting playback is needed, but provides no explicit guidance on when to use this tool versus alternatives like 'play_index' or 'resume'. The parameter description mentions 'If None, uses the current device', which offers some contextual hint but doesn't constitute comprehensive usage guidelines.

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