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

No annotations are provided, so the description carries the burden of behavioral disclosure. The verb 'Returns' implies a read-only operation, and the note about base properties being available in all themes adds useful context. However, it lacks explicit statements about auth requirements, error conditions, or the structure of the returned documentation.

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 description is two sentences, front-loaded with the main action, and contains no filler. Both sentences contribute meaningful information, making it compact and well-structured.

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 lookup tool with two well-described parameters and no output schema, the description is mostly complete. It states what is returned, when to use it, and the availability of base properties. The only minor gap is not describing the exact format of the returned CSS property list, but this is not critical for a straightforward lookup.

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 provides 100% coverage with enum descriptions for both parameters. The description adds value beyond the schema by explaining that base properties (--vaadin-*) are available in all themes, which clarifies the meaning of the 'base' theme option. This extra context justifies an above-baseline score.

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 clearly states the tool returns CSS custom properties documentation for a specific Vaadin theme, naming Aura, Lumo, and Base styles. This specific verb-resource pairing distinguishes it from sibling tools like get_component_styling, which focus on component-level styling.

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 says to use this tool to look up correct CSS variables for the application's theme, providing clear context for when to invoke it. It does not mention exclusions or alternatives, but the defined use case is sufficient for selection.

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