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

With readOnlyHint and openWorldHint already declared, the description still adds real behavioral context: results are ranked best-match-first, an unknown iconId is refused, and emoji- ids render differently in the viewer versus a PNG preview. The one gap is it says nothing about rate limits or result-set size behavior beyond the schema's limit.

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 is front-loaded correctly, but the prose is dense and the final sentence about emoji-id rendering in the viewer is convoluted and tangential to selecting or invoking the tool. Some sentences do not clearly earn their place.

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?

An output schema exists, so return values need no explanation, and the annotations cover the safety profile. The description adds the icon-set scope, id semantics and the emoji quirk, leaving only usage-routing guidance missing for a complete picture.

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 100%, so both query and limit are already documented in the schema; the description's gloss on query ('what they show') adds no syntax or format detail beyond it. Baseline 3 is appropriate when the schema carries the parameter burden.

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 ('Find icons by what they show') plus the scope of the catalog (line-art set and Technology set with named examples like aws-lambda, postgresql, kafka). No sibling tool overlaps with icon search, so the agent can identify this unambiguously.

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?

Usage is only implied: the description explains that a hit's id is what an element's iconId takes, which hints at when you'd call it, but never states when to prefer this over alternatives or what prerequisites exist. No exclusions or conditions are given.

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