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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds genuine behavioral context beyond that: full lower-48 plus DC coverage, both directions (outbound and inbound), single truck type, and that each state's outbound rate is benchmarked against the national average.

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?

A single dense sentence with no filler; geographic scope, directionality, equipment constraint, and the national-average comparison are all front-loaded.

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 one optional parameter and no output schema, the description carries the return-value burden and does so: it states the metric (rate per mile), both directions, the entities covered, and the national-average comparison. Only data freshness is unstated, a minor gap for a rates lookup.

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% and the single equipment parameter is already enumerated with its default documented in the schema. The description only reinforces that one truck type applies per call, adding little beyond the structured field.

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 (rate per mile), scope (every lower-48 state and DC, outbound and inbound), and a single equipment dimension, plus a comparison to the national average. That scope implicitly separates it from get_national_rates, but no sibling is named explicitly, so the differentiation is inferred rather than stated.

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?

Usage is only implied by scope: an agent can infer this is the state-level view rather than a national or lane-level one. There is no explicit 'use this when' clause, no exclusion pointing to get_national_rates or estimate_lane_rate, and no mention of when the state breakdown is preferable.

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