list_visual_data_roles

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

No annotations are present, so the description carries the burden. It discloses that role metadata is hand-curated and that coverage is reported honestly ('curated | none'), meaning unknown or unsupported visual types will not yield fabricated data. It also explains why the bundled theme schema cannot be used, adding important context about the tool's internal behavior.

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 information-dense and front-loaded, but slightly long. It packs multiple facts (role types, accepted values, field caps, mapping, curation caveat, sibling comparison) into two sentences. Every sentence contributes value, but the density makes it less scannable than ideal.

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 single-parameter discovery tool with no output schema, the description covers the returned content (roles, accepted types, field cap, mapping), the data source caveat, and the honest coverage behavior. It also positions the tool within the sibling landscape, making it contextually complete for an agent to select and invoke.

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 input schema already documents visualType with examples and notes deprecated aliases (100% coverage). The description adds no syntax or format details beyond the schema, so it does not elevate the baseline score of 3.

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 the specific verb 'QUERY' and identifies the resource as 'data roles a visual type takes'. It enumerates concrete content (role types, accepted value kinds, field caps, deprecated mapping) and explicitly distinguishes itself from list_visual_properties as the formatting half, making its purpose unambiguous.

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 clearly scopes when to use this tool: it is 'the role half of the discovery surface' and points to list_visual_properties as the formatting alternative. It also sets expectations about coverage via the 'curated | none' honesty note, giving the agent a decision criterion.

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