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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the description only needs to add context beyond that. It does: the data comes from the live UK Trade Tariff, and the response deliberately omits a duty rate because liability depends on the exporter. That explains an otherwise surprising output gap.

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?

Two sentences, zero padding, and the usage trigger is front-loaded before the scope and output caveat. Every clause carries information the agent needs (when to use, source, and the deliberate absence of a rate).

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 read-only lookup with no output schema, the description covers the trigger, the data source, and the shape of the answer (whether a measure applies, no rate). It stops short of saying what a positive result contains, such as measure names or links, which the locale parameter hints at.

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 description coverage is 100% with only two parameters, so the schema already documents the commodity code format and the locale enum. The description adds no syntax, range, or format detail beyond what the schema states. Baseline 3 is appropriate when the schema carries the parameter burden.

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: checks whether a UK anti-dumping or countervailing duty measure applies to a commodity code for Chinese-origin goods, drawn from the live UK Trade Tariff. It also implicitly separates itself from the sibling find_duty_rate by declaring it deliberately returns no rate. An agent can route between the two without opening either schema.

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?

Gives an explicit trigger: 'Use when the user asks whether extra anti-dumping or countervailing duty applies to goods from China.' The statement that it deliberately gives no rate also signals the negative case, steering rate questions elsewhere, though it never names the alternative tool (find_duty_rate) so the agent must infer it.

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