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

Annotations already cover safety (readOnlyHint=true, openWorldHint=false). The description adds meaningful context beyond them: it discloses that the returned figures are reference data that must be re-verified with a local agent before finalizing — an important reliability caveat for a lookup tool. It stops short of saying how data is sourced or refreshed.

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 core statement is front-loaded and efficient, but the Vietnamese sentence largely restates the English content plus the caveat, so roughly half the text is duplicative. It is short overall, but not every sentence 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 single-parameter, no-output-schema read tool with annotations, coverage is adequate: it says what facts come back and warns about verification. The notable gap is that no product/HS code is accepted yet duty rates normally depend on the goods, leaving an agent unclear about the granularity of the returned rates.

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?

Only one parameter exists and schema description coverage is 100%, so the schema already documents the destination country with its own example. The description reinforces that the lookup is keyed on destination country but adds no syntax or format guidance beyond the schema, so the baseline 3 applies.

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 names a specific verb+resource: looking up destination import facts (duty rate, origin preferences, required documents) for third-country direct trade, and even gives a worked example. It does not, however, distinguish itself from close siblings like tra_thue or tra_thu_tuc_nhap_khau, which appear to overlap on duty and procedure lookups.

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?

Usage is implied by the 'third-country direct trade' scoping and the closing caveat to verify with a local agent before finalizing, which signals this is advisory reference data. But no explicit when-to-use/when-not or alternative (e.g., when to prefer tra_thue for tariff details) is stated despite several overlapping siblings.

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