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

Beyond the annotations, it discloses the return contract (slugs for a downstream tool), default source, CC0 licensing for Poly Haven, and the Sketchfab integration prerequisite. It doesn't mention rate limits or side-effect behavior, and the readOnlyHint=false annotation makes the safety profile slightly ambiguous for a search tool, but there is no direct contradiction.

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?

The description is information-dense with the core purpose front-loaded in the first clause. Each sentence adds real value, though the long parentheticals make it slightly harder to parse; a bulleted source breakdown would improve scannability without adding length.

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?

Given the full parameter schema, output schema, and annotations, the description provides the missing operational context: what the returned slugs are for, which source needs setup, which source is restricted, and licensing requirements. Nothing essential is missing for an agent to decide to call this tool.

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?

The schema already documents all four parameters with 100% coverage, so the baseline is 3. The description adds meaning beyond the schema by explaining source-specific behavior: default source, no setup, type=model restriction, integration requirement, and license obligation. It does not add new detail for limit/query, but the schema covers them.

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?

The description uses a specific verb and resource: 'Search free 3D asset sources by keyword' and clearly states the output ('returns slugs for asset_library_import'). It also distinguishes the two supported catalogs (Poly Haven vs Sketchfab), so an agent can separate it from asset_import, asset_generate_3d, and assets_categories.

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?

It gives explicit selection guidance inside the tool: Poly Haven is the default and needs no setup, while Sketchfab requires integrations_set and is limited to type=model with license obligations. It doesn't explicitly name sibling alternatives or state when not to use the tool, but the setup and source-specific conditions are strong practical guidance.

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