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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses pricing ($0.002 USDC per successful call), payment mechanisms (x402 on Base, Solana, or Arc), and that failed calls are not charged. It also states important behavioral constraints: US tariff only, no VAT, no other countries, and duty amount only when the general rate is ad valorem.

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 keeps only high-value information: scope, output fields, exclusions, and price/payment behavior. Every sentence earns its place without redundant 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?

With an output schema present and annotations covering safety, the description provides enough context to call the tool correctly: query semantics, optional customs value, scope limitations, and payment behavior. No critical information appears missing for this lookup tool.

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 baseline is 3. The description adds meaningful semantics beyond the schema by explaining code-prefix matching, keyword lookup, and the condition that the duty amount is computed only when the general rate is ad valorem.

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 gives a specific verb and resource: United States import duty lookup from the USITC Harmonized Tariff Schedule, with HTS code/keyword matching and duty computation. It also clearly scopes the tool against sibling tariff tools by stating 'US tariff only; no VAT, no other countries,' which distinguishes it from EU, China, Japan, and UK tariff tools.

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 clearly states the intended use case and exclusions: US import duty lookup only, no VAT, no other countries. However, it does not explicitly name alternative sibling tools or say when to use those instead, so it stops short of full when-to-use/when-not/alternatives guidance.

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