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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false), and the description adds substantial behavior context beyond them: unit guessing and reporting, the watertightness report, and the crucial note that `repair` moves geometry and defaults off. This meaningfully informs invocation strategy.

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?

Three sentences, front-loaded with the purpose and formats, and each sentence carries actionable content (unit handling, watertightness consequence, repair workflow). It is dense but no sentence is pure filler; the final sentence is slightly overloaded.

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?

With no output schema and 7 optional parameters, the description does the necessary work of explaining the return signals (unit guess, watertightness). It covers the key decision points for a complex import tool, though it omits error/failure modes and how it relates to the create_upload/import_2d siblings.

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 100%, so the baseline is 3 and the schema already documents every parameter richly. The description adds format-specific meaning not in the schema — that STL and OBJ carry no unit and the guess is reported back — which marginally raises it above baseline.

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 (import) and resource (STL/OBJ/3MF mesh file) and adds scope: it produces a new project 'for geometry you did not author.' An agent can distinguish it from import_2d and other import/create siblings from the description alone.

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?

Gives clear operational guidance: pass `unit` when known, check `watertight` before building booleans, and import once then re-import with `repair` only if the mesh is not watertight. It lacks an explicit when-to-use-vs-alternative routing (e.g. vs import_2d or create_upload), which the schema mentions but the description does not.

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