playlists_get_active_announcement_thumbnail

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 states a read operation ('Get'), implying it's likely non-destructive, but doesn't specify permissions, rate limits, error conditions, or the return format (e.g., image data, URL). For a tool with no annotations, this leaves significant gaps in understanding its behavior and constraints.

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, efficient sentence that directly states the tool's purpose without unnecessary words. It is front-loaded with the core action ('Get thumbnail'), making it easy to parse and understand quickly, with zero wasted information.

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 complexity of retrieving a thumbnail (which may involve media handling) and the lack of annotations and output schema, the description is incomplete. It doesn't explain what the thumbnail represents, the format of the return value, or any dependencies on active announcements, making it inadequate for an agent to use the tool effectively without additional 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 100% description coverage, with clear documentation for 'index' and 'cueIndex'. The description adds no additional parameter semantics beyond what the schema provides, such as explaining what these indices refer to in the context of playlist announcements. Given the high schema coverage, a baseline score of 3 is appropriate, as the schema does the heavy lifting.

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 verb ('Get') and resource ('thumbnail for active playlist announcement item'), making the purpose specific and understandable. However, it doesn't explicitly distinguish this tool from sibling tools like 'playlists_get_active_presentation_thumbnail' or 'playlists_get_thumbnail', which also retrieve thumbnails but for different resources, leaving room for confusion about scope differentiation.

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. With many sibling tools involving thumbnails (e.g., 'playlists_get_active_presentation_thumbnail', 'playlists_get_thumbnail'), there is no indication of context, prerequisites, or exclusions, leaving the agent to infer usage based on naming alone.

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