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

Annotations already declare it read-only, idempotent, non-destructive and closed-world, and the description adds substantial extra context: it is rebuilt several times a day, every figure carries date and source, failed figures are surfaced as held back with a reason rather than hidden, and it does not count toward the estimate allowance. That freshness, quality-control and quota information goes well beyond the annotations.

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?

The entry-point guidance is front-loaded and every clause maps to something an agent needs (contents, data provenance, held-back behavior, caching/citation rule, quota). It is a dense single paragraph rather than a run-on, though it is long enough that a structure break would help.

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 and no parameters, the description carries the full burden and discharges it by enumerating the return payload, its provenance, and how withheld figures appear. An agent has everything needed to call it and interpret the result.

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?

Zero parameters, so the baseline is 4. The description explicitly confirms 'no inputs,' which matches the empty schema, but there is no additional parameter meaning to convey.

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 concrete verb and resource ('daily freight brief in one call') and enumerates exactly what the call returns (truckload rates, diesel, outlook, capacity, rail/ocean/air/barge readings, stories). The opening 'Start here for any general freight market question' positions it against the narrower siblings like get_market_snapshot and the estimate_* tools.

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?

'Start here for any general freight market question' gives clear entry-point guidance, and the enumerated contents imply which specific questions it covers. It stops short of naming an alternative tool or stating exclusions, so it falls below the explicit when/when-not bar.

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