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

Annotations already cover the safety profile with readOnlyHint, idempotentHint, and destructiveHint. The description adds meaningful behavioral context: results are ranked, and the tool may deliberately return no catalog match but instead recommend the OS control.

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?

Two sentences with no filler: the core behavior is front-loaded in the first sentence, and the actionable guidance is in the second. Every clause contributes 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 tool with one simple parameter and no output schema, the description adequately conveys input format, output type (ranked components), and the special fallback behavior. Nothing essential is missing for invoking 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?

The schema already documents the only parameter with a concrete example, and coverage is 100%. The description's 'plain language' phrase lightly reinforces natural-language input, but it does not materially add meaning beyond 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 starts with a concrete action and resource: takes a UI need in plain language and returns ranked components. It also highlights the distinctive fallback behavior — recommending the OS's own control when the catalog deliberately lacks an option — which separates it from siblings like list_components or get_component.

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 usage context ('Useful before building a UI control by hand') that tells an agent when to reach for this tool. It does not explicitly name alternatives or state when not to use it, but the guidance is unambiguous for the common case.

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