masks_get_thumbnail

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states it 'gets' a thumbnail (implying a read operation), but doesn't mention any behavioral traits like authentication requirements, rate limits, error conditions, or what format the thumbnail is returned in. For a tool with zero annotation coverage, this leaves significant gaps.

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 communicates the core purpose without any wasted words. It's appropriately sized for a simple tool and front-loads the essential 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?

For a tool with no annotations and no output schema, the description is insufficiently complete. It doesn't explain what the thumbnail output looks like (format, size, encoding), whether this requires specific permissions, or how errors are handled. The context signals indicate this is a simple single-parameter tool, but the description should provide more operational 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 schema description coverage is 100%, so the schema already fully documents the single 'id' parameter. The description doesn't add any additional semantic context about the parameter beyond what's in the schema (e.g., where to find mask IDs, format requirements, or examples). Baseline 3 is appropriate when schema does the documentation work.

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 action ('Get thumbnail') and the target resource ('for a specific mask'), making the purpose immediately understandable. It doesn't explicitly differentiate from sibling tools like 'masks_get' or 'masks_get_all', but those are clearly different operations (getting mask data vs getting thumbnails).

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. There are several thumbnail-related sibling tools (e.g., 'playlists_get_thumbnail', 'props_get_thumbnail', 'themes_get_slide_thumbnail'), but no indication of when this specific mask thumbnail tool is appropriate versus those other thumbnail tools.

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