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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds value by revealing additional behaviors: it checks the official schedule, includes chapter 99 provisions, and notes that export figures are 'when available', which is useful context beyond the 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 sentence that front-loads the primary deliverable (duty rates). It includes multiple details compactly without redundancy, though it could be broken into clearer clauses. Overall, it is efficient.

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?

The tool has only one parameter, the schema fully describes it, and annotations cover the read-only nature. The description explains most return values (duty rates, description path, last-checked date, notes, export figures). It might not specify exact structure or pagination, but with full schema coverage, missing details are minor.

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?

The input schema already provides 100% coverage, including a detailed description of hts_code with the expected format and examples. The tool description does not add new parameter-level semantics, so a baseline of 3 is appropriate.

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 clearly states the tool retrieves official U.S. import duty rates for a single HTS code, listing the specific data fields (duty rates, description path, last-checked date, chapter 99 notes, export figures). It distinguishes itself from the sibling search_us_tariffs by focusing on one HTS code rather than searching.

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 description implies it is for a single, specific HTS code while search_us_tariffs is for searching, providing implicit usage context. It does not explicitly state when NOT to use it (e.g., for multiple codes), but the singular focus is clear.

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