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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive). The description adds behavioral context beyond them: it returns icon names that exist in the target library, and both the query phrasing and `variant` affect ranking/ordering of results.

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?

Three tight sentences, front-loaded with the core action and result, then ranking guidance and the libraryId provenance. No filler.

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 no output schema, the description appropriately states what is returned (icon names) and how ordering works. It does not mention result-count limits or pagination, which is a minor gap for a search 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?

Schema coverage is 100% so the baseline is 3, but the description adds real semantic value: query should be a single noun for best ranking, and variant promotes matching names to the front rather than filtering. This exceeds what the schema fields convey.

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 states a specific verb+resource: 'searches one icon library for icons by concept and returns icon names.' It distinguishes itself from the sibling find-icon-library by scoping to a single library and noting it consumes a libraryId from that other tool.

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 concrete usage advice ('A single noun, such as "inbox", ranks best') and explains how `variant` changes ordering, plus where to get libraryId. It stops short of explicitly stating when not to use it or naming the follow-up install-icons step.

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