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 goes further: it discloses output behavior ('a forecast band is shown only where it has passed a backtest and the source readings are consistent; otherwise the answer says what was held back and why') and a quota trait ('Does not count toward the allowance'). These are valuable behavioral facts not derivable from 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?

Front-loaded with the core purpose, then indices, then omit behavior, then the forecast-band caveat and quota note. It is denser and longer than strictly necessary, but every sentence carries distinct information, so little is wasted.

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 does useful work explaining the forecast-band conditional and quota handling, and the single optional param is fully covered. It could say more about the return shape (e.g., source readings, dates, units per index), which is the remaining gap.

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 enum is documented, but the schema only lists the four enum strings with no meaning. The description adds genuine semantics by labeling each (drewry_wci = Drewry WCI $/40ft container, baltic_dry_index = dry bulk, tac_air_index = air cargo, iata_jet_fuel = jet fuel) and restating the omit/null behavior.

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 verb and resource ('Latest reading and next-period outlook for a global freight index') and enumerates the four supported indices with plain-language meanings. An agent immediately understands the resource is ocean/air freight indices, distinguishing it from rail/barge/market outlook siblings by scope.

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?

Guidance is limited to the parameter ('Omit the index to get all four'), which is really usage of a field. There is no explicit when-to-use or when-not-to-use vs alternatives such as get_market_outlook, get_rail_market_outlook, or ask_freight_analyst, so selection context is only implied by the enumerated indices.

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