get_sketchfab_model_preview

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

With no annotations, the description carries the full burden. It states that the tool 'Returns the model's thumbnail as an Image for visual confirmation,' which discloses the key output behavior. The term 'preview' and the phrase 'before downloading' imply it does not download the full model. However, it does not explicitly mention network usage, caching, or any side effects, but for a simple read-only preview tool, this is sufficient.

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 three sentences, front-loaded with the main purpose followed by usage, parameters, and return value. Every sentence earns its place, with no fluff or repetition. It is appropriately sized for the tool's simplicity.

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 low-complexity tool, the description covers the main purpose, input, and output. However, it fails to document the optional user_prompt parameter, and it does not mention any potential errors or network dependencies. The absence of an output schema increases the need for description completeness, and the missing parameter documentation is a clear gap.

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?

Schema coverage is 0%, so the description must compensate. It explains uid well, including its origin from search_sketchfab_models, but completely omits the optional user_prompt parameter. This leaves a documented schema parameter unexplained, so the description adds some value for one parameter but fails on the other.

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 opens with a specific verb+resource: 'Get a preview thumbnail of a Sketchfab model by its UID.' This clearly states what the tool does and differentiates it from siblings like download_sketchfab_model and search_sketchfab_models, as it focuses on visual preview rather than downloading or searching.

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 explicitly says 'Use this to visually confirm a model before downloading,' providing clear usage context. It also mentions the UID is obtained from search_sketchfab_models, giving a hint about the integration flow. However, it does not explicitly name alternative tools or state when not to use this tool, so it falls just short of a 5.

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