national_stats

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

With no annotations, the description carries the full behavioral burden and does disclose meaningful traits: it is a legacy/backwards-compatible view and contains a 'covered-corpus stats member' alongside the national/by-state data. For a zero-parameter read-only stats tool the risk surface is small, though the return shape (beyond a single phrase) and any error/deprecation behavior are not described.

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?

Two sentences, no filler, with the scope statement front-loaded and the alternative-plus-condition in the second sentence. The phrase 'backwards-compatible covered-corpus stats member' is jargon-heavy and slightly opaque, costing a point.

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 zero-param, no-output-schema stats tool, the description supplies what an agent needs: what data is returned, its geographic granularity, its legacy status, and the preferred alternative. Nothing critical is missing, though the return structure is only loosely characterized.

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 tool takes zero parameters, so per the rubric the baseline is 4. The description adds no parameter information because none exists to explain, and the empty schema is self-evident.

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 names a specific resource and scope: 'NTD GTFS readiness nationally and by state,' which tells an agent exactly what data this tool surfaces. It also flags the tool as legacy and names the sibling it is not (coverage_stats), aiding differentiation. The framing phrase 'United States policy view' is vague, but the substantive clause carries the meaning.

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?

'Prefer coverage_stats for geography-neutral totals' gives an explicit alternative plus the condition that selects it, implying national_stats is for US-specific / by-state needs. It stops short of stating outright when this tool is the right choice or whether it is deprecated, but the routing guidance is clear and actionable.

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