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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, so the safety profile is covered. The description adds real value beyond that: data provenance (FHWA HPMS) and a critical caveat that values are state-reported per roadway section rather than counter readings, which affects how results should be interpreted.

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 tight, front-loaded sentences with no filler; purpose and scope lead. The trailing enumeration of return fields is partially redundant since an output schema exists, costing a bit of efficiency.

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 an output schema present and 100% parameter coverage, the description fills exactly the gaps structured data cannot: data source, reporting caveats, ordering, and the required state prerequisite. Nothing an agent needs to call it correctly is missing.

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?

Schema coverage is 100%, so every parameter including year defaults, radius range (10-5000 m), and limit bounds is already documented in the schema. The description only repeats that 'state is required', adding no syntax or semantic detail beyond structured fields.

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?

States a specific resource (AADT road traffic volume), a precise spatial scope (segments within a radius of lat/lon), and an ordering (busiest first). The radius-based scope inherently separates it from aadt_by_route and aadt_top_segments without ambiguity.

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?

Explicitly states that 'state is required' and routes the agent to aadt_layers to discover valid years, which is a genuine alternative-tool pointer. It does not, however, say when to prefer aadt_by_route or aadt_top_segments over this spatial query.

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