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

Annotations already cover read-only, idempotent, open-world and non-destructive, so the bar is lower; the description still adds real value by disclosing prefix (not exact) matching, that one highway can carry multiple ids (IH0035-KG, IH0035-LG), and that results are ordered busiest-first. It omits any note on result volume or truncation behavior, which is the only remaining behavioral gap.

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?

Front-loaded with the core purpose and source, then the route-prefix rule, then ordering. Dense but every clause carries information; the nested parentheticals make it slightly harder to scan than it needs to be.

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 a full input schema and an output schema, the description only needs to cover matching semantics and result shape, and it does both (prefix matching, multi-id highways, busiest-first ordering). Nothing an agent needs in order 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 baseline is 3, but the description adds semantics the schema does not: route matching is case-insensitive and prefix-based, route_id is state-specific free text, and a single highway may map to several ids. That materially changes how an agent chooses the route value rather than restating the schema.

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 for segments of a named route in one state) with source attribution (FHWA HPMS), and the route-prefix framing makes it clearly distinct from aadt_top_segments and aadt_near_point. An agent can tell exactly what this returns without opening the schema.

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 routes the agent to aadt_top_segments when it needs to discover a state's route_id style, which is the main selection hazard here. It gives concrete per-state id examples (I089, IH0035, SHS_101) but doesn't state when to prefer aadt_near_point or aadt_top_segments for the actual data pull.

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