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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description adds useful context about the reference vocabulary being used by the server. It also adds the evaluative use case, but does not disclose additional behavioral details such as pagination, output shape beyond the schema, or error conditions. The description does not contradict the annotations.

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, front-loaded with the action verb and the full list of enumerated vocabularies, followed by the practical use case. There is no filler, and the structure makes the tool's purpose immediately clear.

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 simple one-parameter listing tool, the description is complete: it identifies the six topic categories, explains why the tool is useful, and notes that it helps construct valid inputs for the other tools. The annotations and output schema cover the remaining operational details, so nothing essential is missing.

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 coverage is 100%, and the schema's parameter description already explains each enum value in detail. The top-level description lists the same categories at a high level but does not materially add meaning beyond the schema. This is the baseline case where the schema does the heavy lifting.

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 uses a specific verb ('Enumerate') and a clear resource ('the reference vocabulary this server uses'), then lists the exact categories. This clearly distinguishes it from the sibling tools, which check, compare, get, or search individual features rather than listing reference vocabularies.

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?

The description explicitly states when to use this tool: 'Use it to build valid inputs for the other tools and to see which target browsers can be evaluated.' It provides solid usage context, though it does not explicitly discuss when not to use it or name alternatives.

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