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

With no annotations, the description carries the full burden and delivers meaningful domain behavior: the 8-digit vs 10-digit inheritance trap, that exclusions are always reported, and that Section 301-type remedies are absent from the data and can dwarf the base rate. It stops short of return format, error handling, or rate limits, but the disclosed caveats are exactly the ones an agent could otherwise get wrong.

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?

Three sentences, each earning its place, with the core verb+resource front-loaded. The inheritance clause is long but conveys non-obvious domain behavior that prevents a wrong answer.

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 two-parameter read tool with no output schema or annotations, the description covers the substantive pitfalls: rate inheritance, exclusions, and FTA checking. It does not mention behavior on malformed or partial codes (e.g., '6212'), which the schema implies is supported.

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%, and the schema already explains that origin_country drives free-trade eligibility, so the description largely restates it. The dot-optional HTS formats are only documented in the schema, not the description. Baseline 3 applies when the schema does the heavy lifting.

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 ('Given a US HTS code, returns the duty rate that actually applies') and the scope is unambiguous. It implicitly separates itself from an estimation tool by stressing the 'actually applies' rate, but it never names the siblings estimate_us_duty or find_hts_code, so differentiation is left to inference.

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 gives one concrete usage hint — pass origin_country to check free-trade eligibility — and scopes out trade remedies, but it never states when to prefer this over estimate_us_duty or when to use find_hts_code first. Usage is implied rather than routed.

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