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

The readOnlyHint annotation already establishes the safe-read profile, so the description's added value is the return shape: each token carries a value per context (light, dark, brand, density). That is genuinely useful output context, but it says nothing about default result size, pagination, or behavior when no prefix is supplied.

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 short sentences with no filler, front-loaded with the resource being returned. The filtering example and the Tailwind utility mapping each 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?

For a read-only list tool with no output schema and two undocumented parameters, the description covers the resource, its multi-context values, and prefix filtering reasonably well. It still leaves the limit/pagination behavior and the no-filter default completely unstated.

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 must carry the parameter burden. It explains 'prefix' with concrete examples ('--nq-danger' or 'surface'), which usefully reveals that both full custom-property names and bare words match, but it never mentions the 'limit' parameter or its maximum of 500.

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 identifies the resource precisely: 'CSS custom properties (--nq-*) with their value in each context (light, dark, brand, density)'. This clearly separates it from component-oriented siblings like get_component and list_components, though it never states the act of listing or enumerating and relies on the tool name for that verb.

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?

There is no statement of when to call this tool versus alternatives such as get_foundation or get_setup, and no prerequisites or exclusions. The Tailwind sentence describes what to do with the returned values, not when the tool itself should be invoked.

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