preview_image

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

With no annotations provided, the description must fully disclose behavioral traits. It mentions 'orientation-corrected' (a useful behavior), but omits critical details: whether the operation is read-only, auth requirements, error handling (e.g., missing image), or performance implications. The description is minimal and 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 sentence of 7 words, which is very concise. It is front-loaded with the key action. However, it could be more structured by separating the preview and metadata aspects, or by adding a second sentence for usage. It earns its place but is slightly underspecified.

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 has 5 parameters, no annotations, and an output schema exists, the description is too sparse. It does not explain the output (though the output schema may cover that), and it lacks context on when to use this tool versus siblings, prerequisites, or error conditions. The minimal description leaves the agent with many unknowns.

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 100% - every parameter already has a description in the input schema. The tool description adds no additional meaning or context for any parameter. According to the rubric, baseline is 3 when coverage is high, and the description does not compensate or provide extra value beyond the schema.

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 clear verb ('Return') and resource ('orientation-corrected preview and size metadata'), which is specific and actionable. However, it does not distinguish this tool from the sibling 'preview_annotations', which may also return a preview. The phrase 'orientation-corrected' adds useful specificity.

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?

No guidance is provided on when to use this tool versus alternatives (e.g., preview_annotations, list_images). There is no mention of prerequisites, context, or exclusions. The description implicitly suggests usage for getting a preview, but lacks explicit directive.

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