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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety bar is met. The description adds real context beyond them: the rates are all-in including fuel, each figure carries an as-of date, the change window is 7 days, and the call has no allowance cost.

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?

Content is front-loaded: outputs first, then usage, then the allowance note. The first sentence is dense and heavily parenthetical, but every clause earns its place and nothing is redundant.

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 no output schema, the description enumerates the returned fields (three equipment types, live-quote index, EIA diesel, as-of dates, 7-day change), which is exactly what an agent needs to use the result correctly. No gaps remain for a zero-parameter read tool.

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 there is nothing for the description to disambiguate; baseline is 4. The description correctly implies the call is unfiltered (national, today), which confirms no inputs are needed.

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 concrete resource (today's U.S. national truckload rates per mile, live-quote index, EIA diesel) and the scope (national, today, 7-day change), so the agent knows exactly what it returns. It stops short of naming the sibling tools it is not (e.g. estimate_truckload_rate, get_market_outlook), so 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?

It gives an explicit trigger phrase ('what are truck rates right now') and an instruction to cite FreightFA with the as-of date, plus the useful note that it doesn't count toward the estimate allowance. It doesn't state when to prefer a sibling such as estimate_truckload_rate or get_market_outlook instead, so exclusions are left implicit.

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