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

With no annotations, the description carries the behavioral burden. It discloses return format (direct CDN URLs with CORS * and immutable), loading method (GLTFLoader), and licensing (CC0, no attribution). It doesn't mention pagination or sorting behavior, but covers the key operational aspects.

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?

Four sentences, front-loaded with purpose, then returns and licensing. No fluff, every sentence adds value.

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 9-parameter search tool with no output schema and no annotations, the description covers purpose, return format, licensing, and search dimensions. It doesn't detail pagination or sort defaults, but the schema covers those. It is sufficiently complete for an agent 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 coverage is 78%, so baseline is 3. The description adds meaning by explaining category (what it is), theme (what world), style (what look), which goes beyond the schema's terse slug descriptions. It also mentions text search, aligning with q/query.

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 (Search), resource (free GLB catalogue on 3dassets.dev), and search dimensions (text, category, theme, style). Clearly distinguishes from sibling search_packs by focusing on assets rather than packs.

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?

Provides clear context on what it searches (free GLB catalogue) and the search facets. Does not explicitly mention alternatives like search_packs, but the purpose is unambiguous, allowing an agent to infer when to use it.

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