Export 3D model (OBJ / STL / GSM)

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

Annotations only give a coarse safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=false); the description adds real behavioral context beyond them: the side-effect of writing an adjacent .mtl file, the source-vs-window dependency, coordinate/up-axis conventions per format, and default units. It does not restate the overwrite/error semantics already in the schema, but the extra file side-effect is a meaningful disclosure.

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?

Two dense, front-loaded sentences that lead with the formats and defer source/coordinate/return details. Mostly efficient, though it repeats schema defaults (units m, binary) that the schema already carries, costing a little tightness.

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 16-parameter export tool with no output schema, the description is complete: it names the formats, sources, coordinate/unit conventions, and even the return shape ({file, materialFile?, counts, boundingBox}), so an agent has everything needed to call it correctly.

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%, so a baseline of 3 applies, but the description adds genuine cross-parameter meaning: it clarifies the interaction between source, elements, and useSelection ('Without elements/useSelection'), and the per-format defaults for up-axis and binary. This is more than restatement of the schema text.

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 (Exports) plus the resource (3D geometry) and enumerates the exact output formats with their distinguishing traits (.obj with .mtl, binary triangulated .stl, .gsm GDL object). An agent can distinguish this from the many create_*/modify_* siblings and from export_ifc/dwg/pdf at a glance.

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 context for the default path: 'Source: what the 3D window shows (default — set it up first with the views tools, e.g. show selected elements in 3D, 3D cutaway)'. It also explains how elements/useSelection/AllElements select alternative sources. No explicit when-not or named export-format alternatives, so it stops short of a 5.

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