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

With only a title annotation, the description carries the burden and does add real context: model trade-offs (trellis-2 default/best price vs tripo high-quality/PBR/≤20k faces/pricier) and share-link auto-resolution behavior. It omits async/long-running lifecycle and how results are retrieved (via var2_get_3d_result), which are meaningful gaps for a generation tool.

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?

Front-loaded with the core capability, then routing rules and model trade-offs in dense arrow notation. Very efficient, though the telegraphic style is terse and slightly hard to parse.

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?

There is no output schema, so the description should explain what calling it returns (job id? polling?), which it does not. It also leaves resolution/texture_size undefined and only implies the async lifecycle. Adequate for routing but incomplete for correct invocation mechanics.

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 60%. The description enriches the image param (storage URL, share link, or any https URL — pass the link the user gave) and the model param (default and pricing tiers). But resolution and texture_size enums have no semantics in either schema or description, leaving genuine gaps.

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: produce a 3D mesh (.glb) from ONE image. It explicitly distinguishes itself from siblings — routing image-share-link actions here rather than to a status tool, and naming var2_create_image / var2_upload_asset as prerequisites. An agent can tell it apart from var2_get_3d_result without opening schemas.

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 explicit when-to-use triggers ("Make a 3d model of this image/character"), when-to-use alternatives (no image → var2_create_image first; local file → var2_upload_asset first), and a subtle routing rule for var2.ai/image share links. It even warns against fabricating the URL.

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