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

Annotations already mark this as read-only and non-destructive; the description adds important behavioral context: the tool queries the live UK Trade Tariff and intentionally omits the rate because it depends on the exporter. This tells the agent what to expect and prevents false assumptions about output.

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 two purposeful sentences with no filler. The first sentence front-loads the tool's scope and data source; the second delivers the key limitation. Every word earns its place.

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 low-complexity existence check, the description, schema, and annotations cover the required inputs, the live read-only nature, and the key limitation about rates. With no output schema, a more explicit pointer to an alternative rate-lookup tool would make it fully complete, but nothing essential for correct invocation 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 description coverage is 100%, so the schema already documents both parameters fully. The description adds little beyond the schema for parameter semantics; it mentions commodity codes but does not provide additional meaning over the structured field descriptions.

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 a specific verb and resource: it checks whether a UK anti-dumping or countervailing measure applies to Chinese goods on a commodity code, using the live UK Trade Tariff. This clearly differentiates it from siblings like find_duty_rate by focusing on measure existence rather than a rate.

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 provides clear context for when to use this tool: when determining whether a UK anti-dumping/countervailing measure applies to goods from China on a commodity code. It does not explicitly name an alternative for rate lookup, but the emphatic 'Deliberately gives no rate' guides the agent away from using it for rate calculations.

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