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

Annotations already declare readOnly and closed-world, so the description adds domain behavior instead: CC0 licensing, .glb format, rigged models exposing named animation clips, and that results include direct asset URLs. This is genuinely useful context beyond the structured fields; only rate-limit/pagination behavior is absent.

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 tight sentences, front-loaded with what the tool returns and the most useful operational hints; no filler or repetition of schema text.

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, and the description covers the essential return shape (direct .glb URL per model) plus animation-clip semantics. Adequate for a zero-required-param read tool; only result-ordering/pagination details are unstated.

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 all four parameters are already documented in the schema. The description only adds the empty-query semantics ('leave query empty to list everything of a kind'); it says nothing extra about kind, limit, or animated beyond what the schema states, so baseline 3 applies.

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 — searching Gobkit's free CC0 low-poly .glb models — plus the distinguishing traits (rigged/animated vs static, direct URL returns). An agent can distinguish this from get_model (single fetch) and list_packs (pack listing) without opening any 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?

Gives a concrete operational rule: leave query empty to list everything of a kind, and use named animation clips on rigged models. It does not explicitly name when to prefer get_model or list_packs, but the usage context is clear.

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