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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so safety needs no restating. The description adds value beyond that by disclosing an access-tier dependency — full access yields the complete DESIGN.md for the top result — which is a real behavioral constraint an agent should anticipate.

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 purpose and return contents are front-loaded, and the query-grammar sentence is dense but informative. It is two long sentences with little waste, though the facet list plus the DESIGN.md note could be tightened slightly.

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 an output schema present, return-value explanation is optional, yet the description still sketches result contents and the access-gated DESIGN.md, and annotations carry the safety profile. The only real gap is sibling routing, which matters given find_ui_references sits alongside it.

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 the baseline is 3, but the description earns extra by decomposing 'query' into a facet taxonomy (industry, theme, brand color, style, font, site name) and showing how facets combine, which the schema's short example list does not spell out. The 'limit' parameter is left entirely to the schema.

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 names a specific verb and resource — searching UXKIN's design systems sourced from real websites — and enumerates what each result contains (colors with roles, typography, components, DESIGN.md for the top hit). That is far more concrete than a generic 'search' tool, but it never differentiates itself from the sibling find_ui_references, leaving the agent to infer which retrieval tool to pick.

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 clear operational guidance: query by industry, theme, brand color, style, font, or site name, and combine facets ('dark fintech'), plus the specific trick of searching a site by name to get its DESIGN.md. What is missing is any explicit when-not/when-else routing against find_ui_references or the collection tools.

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