Get page thumbnail of Docling document

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds that the thumbnail is derived from a local-cache document, but says nothing about whether the thumbnail is persisted/side-effecting, what format is returned, or any cost/size considerations—important for a 'generate' verb.

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?

A single front-loaded sentence with no filler. Nothing is redundant or buried.

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?

No output schema exists, so the description should explain what the thumbnail return looks like (image bytes, URL, base64, MIME type) and any prerequisites. It covers neither, leaving the agent guessing about the result shape.

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%, with size, page_no, and document_key fully documented, so the schema carries the burden. The description only echoes 'requested page' without adding defaults, units, or format semantics 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?

States a specific verb+resource: generating a thumbnail image for a requested page of a cached document. It's distinguishable from the anchor/text-reading siblings in the toolset, though it doesn't say how it relates to get_overview_of_document_anchors or other read tools.

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 explicit guidance on when to use this versus alternatives, and no stated precondition that the document must already be in the local cache (e.g., via check_document_in_local_cache or convert_document_into_docling_document). The phrase 'in the local cache' only hints at the requirement.

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