get_playlist_cover

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 only states 'Get' (implying read-only) but does not reveal any behaviors such as error handling, authentication prerequisites, or whether the URLs are for multiple sizes. It does not mention what happens if a playlist has no cover, nor any rate-limiting considerations. This is a significant gap for a tool with zero annotation support.

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 a single sentence with no filler or redundancy, making it concise and front-loaded with the core purpose. It earns a 'concise' rating, though it might be considered overly terse given the lack of auxiliary information. Still, as a structure, it is efficient and easy to parse.

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 (one parameter, no output schema, no annotations), the description is thin. It fails to mention what the response looks like (e.g., an array of URLs, default images) or any edge cases. Since annotations and output schema are absent, the description should compensate with more detail, but it does not. The tool is functionally callable, but an agent lacks context on expected return values or failure modes.

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 schema description coverage is 100% (playlist_id has a clear description 'Playlist ID'), so the schema fully documents the parameter. The tool description adds no additional meaning about the parameter's format, constraints, or usage nuances. According to the rubric, a baseline of 3 is appropriate when schema coverage is high and the description does not add extra semantics.

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 states a specific verb ('Get') and resource ('playlist's cover image URLs'), which clearly distinguishes it from siblings like upload_playlist_cover (an upload) and get_playlist (which may return broader playlist data). However, it does not explicitly differentiate it from get_playlist, which could also return cover images, so a clear purpose is present but sibling differentiation is implicit.

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 no guidance on when to use this tool versus alternatives. It does not mention that get_playlist might be a more comprehensive choice, or that this tool is specifically for fetching cover image URLs. No when-not-to-use or alternative routing is given, leaving the agent without explicit usage context.

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