List thumbnail sizes

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

The readOnlyHint annotation already establishes that this is a read-only operation. The description adds a small behavioral nuance: it lists only thumbnail sizes that Onshape has actually rendered, and it includes hrefs. This is consistent with the annotation and provides slight extra context, but no deeper behavior (such as pagination or auth requirements) is disclosed.

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 short sentence that directly conveys the tool's output. It is front-loaded and contains no filler, making it easy for an agent to parse quickly.

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 simple read-only listing tool, the description plus the well-documented schema covers the essentials: which element to target and what the output contains (thumbnail sizes and hrefs). It does not detail the return structure or explain the relationship to onshape_get_thumbnail, but the data shape is simple enough that an agent can proceed without that detail.

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%: doc, ws, and elem all have clear explanations referencing document/workspace/element URL segments. The description adds no additional parameter meaning, so the baseline of 3 applies.

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 identifies the resource ('thumbnail sizes' for an element) and notes the output includes their hrefs, making it clear this is a metadata-listing tool rather than a thumbnail fetcher. However, it lacks an explicit verb such as 'lists' or 'returns', and it does not distinguish itself from the sibling tool onshape_get_thumbnail by name.

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 onshape_get_thumbnail or other related tools. The description only states what the tool returns, leaving the agent to infer appropriate usage.

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