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

With no annotations, the description carries the full burden and does well: it discloses the complete output set, accepted file formats, a units contract, a content restriction (no weapons/firearms/ammunition/explosives), and even the cost (1 credit per call). It still omits permission/auth requirements and any input-size or processing-limit caveats, so it stops short of a 5.

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 dense paragraph that front-loads the core action, then the return artifacts, then units, restrictions and cost — every clause carries information. It is long, but the length is justified by six undocumented parameters and a missing output schema; a bulleted split of inputs vs outputs would read better than the run-on list.

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 tool with no annotations and no output schema, the description covers inputs, the full set of return artifacts (dimensions, volume, mass, weight by material, cross-sections, hulls, DXF, re-exported STL, viewer), units, refusal policy and cost. Nothing an agent needs in order to call it correctly is missing, aside from the minor param gaps noted above.

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 0%, so the description must compensate, and it does for most parameters: it explains unit ("unit: mm|cm|m|in ... default mm"), the format enum via the listed file types (STL binary/ASCII, OBJ, ASCII PLY), and the two data channels (data_base64 vs data_text). It does not explain the material enum values or what title is used for, leaving two of six parameters undocumented in both places.

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 (reverse engineer a part from a 3D scan/mesh) and enumerates the concrete artifacts produced, which cleanly separates it from the cad_build/cad_part/cad_fusion siblings that generate rather than reconstruct CAD. An agent can identify the tool's purpose without opening the 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?

The description implies when to use it (you have a scan/mesh and need CAD drawings, specs or measurements) and names the accepted input formats, so the trigger condition is reasonably clear. However, it never names an alternative sibling or states when NOT to use it, and it doesn't mention that data_base64 or data_text must actually be supplied for the call to do anything.

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