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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety is covered. The description adds real value beyond that by spelling out the response payload categories, which matters because there is no output schema. It stops short of noting data provenance/freshness (FMCSA licensing & insurance records) or any lookup-failure behavior for unknown DOT numbers.

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?

Purpose and return fields are front-loaded in the first two sentences, which is the right structure. The trailing list of seven paraphrased example questions is somewhat padded but does real work for query-to-tool matching, so it mostly earns its place.

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 single-param, read-only lookup with no output schema, the description covers what it checks, what it returns, and what user questions it answers. With annotations and the schema covering safety and identifier format respectively, nothing essential to correct invocation 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?

There is a single parameter with 100% schema description coverage ('USDOT carrier identifier as a positive integer, e.g. 76830'), so the schema already carries the semantics. The description adds no format, identifier-source, or validation guidance beyond it, making this a baseline 3.

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 uses a specific verb+resource ('Check if a trucking company is legally authorized... has valid insurance') and enumerates the exact fields returned (operating authority status, BIPD, cargo, bond/surety). It implicitly separates itself from fmcsa_safety_scores and fmcsa_carrier_search by framing the tool as an authority/insurance compliance check, but it never names those siblings explicitly.

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?

A long list of concrete triggering questions ('can this carrier legally operate?', 'is this broker licensed?', 'is this freight company legit?') makes the intended use unambiguous. However, it gives no exclusions or pointer to fmcsa_carrier_lookup / fmcsa_carrier_compare / fmcsa_safety_scores when the agent actually needs those instead.

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