Now Playing

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

Annotations already establish read-only, idempotent, and open-world behavior. The description adds useful behavioral detail not in annotations: it returns a PlaybackState and explicitly notes that is_playing is False when nothing is playing, which clarifies an edge case.

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?

Two sentences, front-loaded with the core purpose and followed by a useful return-value note. Every sentence earns its place with no redundancy or filler.

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 zero parameters, rich annotations, and an output schema, this description is complete for correct invocation by an agent. It states what the tool returns and even covers the nothing-playing case.

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 tool has zero parameters, so the baseline is 4. The description correctly lists the returned fields instead of inventing parameter semantics, and no parameter documentation is needed.

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?

Describes the action and resource clearly: 'Get the current playback state' followed by concrete fields (track, device, progress, shuffle, repeat). This makes the purpose unambiguous, though it doesn't explicitly contrast with sibling tools such as control_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 implies the tool is for reading current playback information, and the read-only annotations reinforce that. However, it offers no explicit guidance on when to prefer this tool over alternatives like get_queue, list_devices, or control_playback.

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