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

Annotations already cover readOnly, idempotent, and openWorld hints. The description goes beyond these by disclosing the never-empty-list guarantee and explaining the three distinct failure reasons (nothing digitized, non-image media, non-CC0 images). It also describes the output structure (thumbnail, screen-size, high-res URLs with pixel dimensions), providing meaningful behavioral context without contradicting annotations.

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 reasonably concise given the amount of behavioral detail it conveys. It front-loads the core purpose, then efficiently covers edge cases and output structure. Each sentence contributes information, though it could be slightly tightened without loss. Overall it is well structured and not padded.

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 single-parameter, read-only tool with an existing output schema and annotations covering safety, the description provides complete operational context. It covers the main behavior, failure modes, output characteristics, and even cross-references a sibling tool's filter for workflow integration. Nothing essential is missing.

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 description coverage is 100% for the single 'id' parameter, including a format example and source references. The description does not add additional semantic detail about the parameter beyond what the schema already provides, so the baseline of 3 is appropriate.

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 ('Return'), a specific resource ('every CC0 image for a Smithsonian object'), and the scope ('at multiple resolutions'). It clearly distinguishes itself from sibling tools that handle search, browsing, or related-objects, and the mention of the cc0_only filter on smithsonian_search_objects further differentiates the workflow.

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 gives a clear usage hint by pointing to the cc0_only filter on smithsonian_search_objects, implying the agent should search first to find objects with downloadable CC0 images and then call this tool with the record_id. However, it does not explicitly state when *not* to use this tool or list alternatives for other scenarios, so it lacks full exclusion guidance.

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