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

Annotations already declare a safe read-only, closed-world operation, and the description goes well beyond that: it discloses partial/no-preview limitations for Creo and CATIA files, unverified units, the thumbnail-only fallback, and the ~1-hour deletion window. These are meaningful behavioral traits an agent cannot infer elsewhere.

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?

Purpose is front-loaded and the sentences each carry information. The ~50-entry format list is bulky but serves as legitimate reference data for format eligibility, so it mostly earns its space, though it could be condensed.

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 four-parameter tool with an output schema, the description supplies the formats, caveats, upload workflow, and data-retention details an agent needs. The remaining gaps are minor (wait_seconds behavior, ref continuation), and the output schema covers return values.

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 only 50%, so the description must compensate, and it does for the flow parameters: the no-file call leads to an upload link, the upload_ticket is used after the user confirms upload, and the retention window is stated. It still leaves wait_seconds and the ref-based continuation unaddressed, so it is strong but not complete.

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 and resource ('Open a CAD file... report its format, size, volume, area, units and accuracy') and enumerates exactly what it returns. It is readily distinguishable from convert_cad and open_in_workspace without opening any schema.

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?

It gives real workflow guidance ('Call with no file to get a one-time upload link') and the upload-ticket handoff, which frames how to invoke it. However, it never states when to prefer this over convert_cad or open_in_workspace, and offers no explicit exclusions, so usage is implied rather than directed.

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