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

Annotations already declare readOnly/destructive/openWorld, but the description adds real value beyond them: it clarifies the tool returns download URLs rather than model bytes, that exporting does not modify saved data, and that OBJ output reuses vertices and drops hidden internal faces (an optimization/wire-size trait).

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 sentences, front-loaded with the core action and output, then the read-only guarantee. No filler or restatement of the name.

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, the description usefully discloses that the return is download URLs, which is the key thing an agent needs. Remaining gaps are minor: no explanation of the 'model' identifier (ID vs name) and no note on URL expiry or size limits.

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. It meaningfully characterizes the format options ('optimized OBJ+MTL' vs 'compact VoxelDraft JSON'), but the required 'model' parameter is left entirely unexplained in both schema and description.

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 ('Compute direct download URLs' for a voxel model export) and names the two output formats. It distinguishes itself implicitly from save/load siblings by framing the result as download URLs rather than persisted files, though it never names a sibling explicitly.

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?

There is no when-to-use guidance and no comparison to alternatives such as save_voxel_model or render_voxel_model. The only inferable guidance is the format choice, which is a parameter concern rather than usage context.

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