naep_gap_variable_years

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

Annotations already cover the read-only, non-destructive, idempotent nature of the tool, so the description does not need to repeat that. It adds useful behavioral context by specifying exactly what is returned: the group gap for the focal year, the group gap for the target year, and the gap between them.

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 concise: a purpose statement, one illustrative example, and a compact list of returned values. It is front-loaded with the main purpose and contains no filler, though the example and return list could arguably be merged.

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?

With no output schema, the description does well to name the returned fields and give a concrete example. However, it leaves ambiguity about how the 'years' parameter maps to focal vs target year and how to interpret the sign of the final difference, and it provides no guidance for choosing among the sibling NAEP gap/compare tools.

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 describes all five parameters (100% coverage), so the baseline is 3. The description adds the 'focal year' / 'target year' interpretation and a demographic-group framing, but it does not clarify whether the first comma-separated year is focal or target, leaving some ordering ambiguity.

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 operation: comparing achievement gaps between demographic groups over time, and it enumerates the returned values (innerdiff1, innerdiff2, and the difference between them). It does not explicitly distinguish itself from sibling NAEP tools such as naep_compare_years or naep_gap_variable_jurisdiction, so it falls just short of a 5.

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 example question ('Is the racial achievement gap in reading getting bigger or smaller since 2017?') implies when the tool should be used, but the description never states when not to use it or names an alternative sibling tool. Usage context is implied rather than explicit.

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