spotify_is_playing

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns 'true' or 'false' as text, indicating a simple read operation with no side effects. For a zero-parameter, non-destructive tool, this is sufficient behavioral context. No contradictions noted.

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 extremely concise: two sentences that immediately state the core functionality and a use case. Every word serves a purpose. No extraneous information. Front-loaded with 'Get ONLY whether...' which is the essential purpose.

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 the tool's simplicity (no parameters, no output schema), the description is complete. It answers: what does it do? (get playing status), what does it return? (true/false text), when to use it? (play/pause HUD states). Sibling tools like spotify_get_playback_state or spotify_get_current_track are implicitly differentiated by the 'ONLY' emphasis. There is no missing context.

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 input schema has zero parameters, so schema description coverage is 100%. The description adds no additional parameter meaning because there are none. Baseline for 0 parameters is 4, and the description doesn't need to compensate beyond confirming no inputs are required.

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 tool's purpose: 'Get ONLY whether music is currently playing.' It emphasizes 'ONLY' to distinguish from more comprehensive tools like spotify_get_playback_state. It specifies the return type ('true' or 'false' as text) and a concrete use case (play/pause button states in HUDs). This is a specific verb+resource with clear differentiation from siblings.

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 provides usage context: 'perfect for play/pause button states in HUDs,' implying when to use this simple boolean check versus sibling tools that provide richer playback state. It doesn't explicitly list alternatives but the 'ONLY' qualifier and use case hint at when-not-to-use. This is clear enough for a straightforward tool.

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