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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the description only needs to add context. It adds the state-dependent 'toggle' semantics and the group scope, but does not describe side effects or result. No contradiction with annotations.

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?

One short sentence with no filler. The verb and scope are front-loaded, and every word contributes meaningful information.

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 one-parameter toggle with no output schema, the description plus schema fully covers the target, effect, and default behavior. Nothing an agent needs to invoke it correctly is missing.

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 single room parameter is fully documented in the schema (English names, Chinese aliases, omit for default). The description adds no parameter-level meaning beyond what the schema already provides, so the 100% schema coverage carries this dimension.

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?

States a specific verb 'toggle' and resource 'play/pause' scoped to 'a room's group.' This clearly distinguishes it from sibling transport controls such as next_track, previous_track, play_music, and adjust_volume without needing to name an alternative.

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 gives the operational context (toggle playback for a room's group) and the schema clarifies room selection, but it does not explicitly say when to choose this tool over alternatives like play_music or seek, nor does it state any exclusions.

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