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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that — the return payload shape, the measured/retina preference flags, and the important relaxation behavior (filters that match nothing relax instead of returning empty). However, it says nothing about pagination, result ordering, or rate limits, so it is additive but not rich.

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?

Front-loaded with purpose and the before-you-design rule, then returns, then the filter-semantics caveat, then Args. Every section earns its place given the zero-coverage schema, though the long inline enumeration lists make it heavier than strictly necessary.

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?

No output schema exists, so the description correctly summarizes the return shape (description, UX patterns, UI elements, colors, palette, image_url, measured/retina). For an 8-parameter, zero-coverage search tool this is close to complete; only pagination/ordering behavior is unaddressed.

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 carries the full burden — and it does: it enumerates the allowed page_type, industry and platform values, gives examples for query/ux_pattern, explains limit bounds (1-40, default 12), defines kind's four modes, and clarifies how section_type pairs with kind. This is exactly what an untyped 8-param schema needs.

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 (search real product UI screens) plus the resource's scope (design reference), and differentiates it from retrieval siblings like get_screen/get_screen_sections by establishing this as the discovery entry point. An agent knows immediately what it gets back: structured metadata plus an image_url.

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?

Explicit prescriptive timing: "Use this BEFORE designing any page/component." It further tells the agent that `query` alone works and that filters are optional, and that near-miss filter values rank rather than exclude — effectively telling the agent when it is safe to skip parameters entirely.

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