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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds context beyond that: it warns that 'Containerised gateway trade and nationwide duty receipts are different universes — the response says so where they sit side by side,' and states that no API key is required. This provides additional operational context without contradicting 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?

The description is a single, information-dense paragraph that front-loads the core purpose, then gives usage guidance, a caveat, and an exclusion. Every sentence contributes value, and it is not overly verbose despite covering many aspects of the tool.

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 lists what the response contains: volume, value, trend, top commodity chapters, gateways, tariff burden, and pre-registered studies. It also clarifies the two different data universes and provides exclusions for other tool uses. This gives a comprehensive picture of the tool's output and scope.

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 50% (origin and top_n have descriptions, detail and months do not). The description partially compensates by referencing 'top commodity chapters' (top_n) and 'the trend' (months), but it does not explain the detail parameter or the specific meaning/constraints of months. It adds marginal value beyond the schema but does not fully cover the undocumented parameters.

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 opens with 'One origin country, whole, in a single call' and explicitly lists the data components (import volume, value, gateways, commodity chapters, tariff burden, studies), giving a clear verb+resource scope. It distinguishes from siblings by explicitly excluding HS-code (tariff_story) and two-way comparison (compare) use cases.

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?

It provides explicit when-to-use guidance: 'Use this to OPEN any country-level question... instead of firing trade_query and tariff_burden separately.' It also gives clear exclusions: 'Do NOT use for a specific HS code (tariff_story) or a two-way comparison (compare).' This covers both positive and negative usage with named alternatives.

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