Playback control

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not mention prerequisites like needing an active player, what 'toggle' actually toggles, side effects, or failure behavior. The description simply restates the action list.

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 one concise sentence with the operation type front-loaded and the action list immediately following. Every word contributes, with no filler or redundant explanation.

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 two-parameter tool, the description plus schema adequately defines the core call mechanics. However, the lack of annotations and absence of usage boundaries around player eligibility and the overlap with play_music leave some contextual 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 description adds some context by framing the actions as transport controls, but mostly repeats the enum values already present in the schema. The 'player' parameter is already documented in the schema, so the description provides minimal additional semantic value beyond the structured data.

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 ('Control transport') and explicitly enumerates all supported actions: play, pause, toggle, stop, next, and previous. This makes the tool's purpose unambiguous and distinguishes it from siblings like play_music or seek.

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 no guidance on when to use this tool versus alternatives. Since play_music also includes a 'play' action, the boundary between playback_control and play_music is not addressed, and no exclusions or preferred contexts are mentioned.

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