list_variables

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

No annotations are provided, so the description carries the full burden. It fails to disclose any behavioral traits such as whether results are paginated (despite a page parameter), the output format, or that it is a read-only operation. The description only adds domain context, not behavioral transparency.

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 action ('List data variables'), and contains no filler. Every word adds value, earning top score for conciseness.

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?

Given 4 optional parameters, no output schema, and no annotations, the description does not provide enough context about how this tool fits into the broader API. It lacks any mention of pagination behavior, relationships to the many sibling list tools (e.g., list_vertical_variables), or what the response might look like. The comprehensive schema partially compensates, but the description is too thin to be considered complete.

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 has 100% description coverage for all four parameters (page, year, domain, subject), so the baseline is 3. The description adds no additional meaning beyond what the schema already provides, so no extra credit is warranted.

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 ('List') and identifies the resource ('data variables in BPS dynamic tables') with examples (Population Count, Poverty Rate). It is clear but does not differentiate from sibling tools like list_vertical_variables or list_derived_variables, so it loses the point for sibling differentiation.

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 guidance on when to use this tool versus alternatives. The description mentions variables determine retrievable data, implying it might be a precursor to data retrieval, but it does not state any explicit use cases, exclusions, or comparisons to the many sibling list tools.

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