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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the description earns credit for disclosing return content instead: the three duty columns, the date last checked against the official schedule, chapter 99 provision notes for additional duties and expired reductions, and export figures only 'when available'. It stops short of stating error behavior for malformed codes or the tariff schedule's jurisdiction/currency assumptions.

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?

One sentence, front-loaded with the verb and primary output, with the secondary returns trailing. It is somewhat of a run-on enumeration, but every clause identifies a distinct part of the response rather than padding.

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?

There is no output schema, so the description must carry the return-value burden, and it does so thoroughly, including the 'when available' caveat on export figures. For a single-parameter read tool with full annotation coverage, this is close to sufficient; only invalid-code handling and schedule currency limits are unstated.

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 single hts_code parameter already includes dotted-format examples, so the schema does the work. The description adds only the framing 'one HTS code' with no format, hierarchy, or partial-code guidance beyond what is structured. 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 ('Get') and resource ('official U.S. import duty rates for one HTS code') and enumerates the payload (general/special/column 2 rates, description path, last-checked date, chapter 99 notes, export figures). 'For one HTS code' implicitly separates it from search_us_tariffs, though the sibling is never named. Clear, but not maximally differentiated from the search tool.

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 phrase 'for one HTS code' implies a single-record lookup versus a search, which is the only usage signal. There is no explicit 'use this when... use search_us_tariffs instead when...' statement, and no mention of what happens with an unknown or invalid code. Usage is inferable but not stated.

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