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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the data source (WITS SDMX API), what the response includes, the default partner behavior, an explicit exclusion (non-tariff measures are not included), and the payment model ($0.002 USDC per successful call, x402 on Base/Solana/Arc, failed calls not charged). This adds substantial behavioral context for a paid, external-data tool.

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 description is front-loaded with the core purpose and resource, followed by scope exclusions and pricing. Every sentence contributes useful information—source, output fields, partner default, non-tariff exclusion, and cost model—with no filler or repetition.

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?

Given the output schema exists, the description need not explain return values. It covers what an agent needs to know before calling: the data source, the exact scope (one country, one HS6, applied tariffs), the default partner, what is excluded, and the payment mechanism. Annotations already cover safety, so nothing material 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?

Schema coverage is 100%, so the schema already documents all four parameters. The description reinforces required parameters ('one importing country and one HS 6-digit product') and clarifies that the partner default means world/MFN, but it does not add syntax, enum, or format details beyond what the schema provides. Baseline 3 is appropriate.

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 states precisely what data is returned: applied import tariffs from World Bank WITS/UNCTAD TRAINS for one importing country and one HS 6-digit product, including average rate, tariff type, min/max line rates, and line count. This clearly differentiates it from country-specific tariff siblings by naming the source and the exact 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?

The description gives clear context—applied tariffs only, non-tariff measures excluded, partner defaults to world (MFN)—but does not explicitly name alternative tools (e.g., logistics_uk_trade_tariff) or state when to prefer them. An agent can infer the use case from the source and scope, but the routing guidance is implicit rather than explicit.

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