play_pause

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

With no annotations, the description carries the full burden. It discloses return statuses ('playing', 'paused', 'no_active_device') and raises ValueError/SpotifyException, providing meaningful behavioral context. Minor gaps: it doesn't explicitly state that playback state changes, though that is inherently clear from the verb 'toggle'.

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 and front-loaded with a one-line summary, followed by concise parameter, returns, and raises sections. Every sentence adds value without redundancy or unnecessary verbosity.

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?

The tool is simple, has an output schema, and the description covers parameters, return values, and error conditions. It is complete for its complexity and leaves no significant gaps for an agent to invoke it correctly.

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?

Input schema has only one parameter 'action' with no description or enum, giving 0% schema coverage. The description fully compensates by listing accepted values ('play', 'pause', 'toggle') and default ('toggle'), adding essential semantic meaning beyond the schema.

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 'Control Spotify playback – play, pause, or toggle the current state' uses a specific verb and resource, clearly differentiating from sibling tools like skip_track or play_context. The action options are explicitly listed, leaving no ambiguity about the tool's core 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?

The description does not provide explicit when-to-use or when-not-to-use guidance compared to alternatives. It implies usage for basic playback control but lacks direct references to sibling tools or exclusion scenarios, so it earns a 'implied usage' score.

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