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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds real behavioral value by disclosing the returned subject matter, notably Section 301 China list status, exclusions, and the 2026 US–China reduction flag, which the agent could not otherwise anticipate.

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?

A single sentence with the resource and accepted input formats front-loaded, followed by the returned fields. Every clause (digit lengths, each rate column, Section 301, exclusions, 2026 flag) carries distinct information; nothing is padded.

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 usefully enumerates the returned fields, so an agent knows what to expect. It does not cover failure modes, such as what happens for an invalid or non-existent code, which is the one remaining gap for a 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% and the schema gives example values, so the baseline is 3. The description goes beyond that by specifying the accepted digit lengths (4, 6, 8 or 10 digits), a validation constraint the schema does not state, which helps the agent avoid malformed invocations.

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?

States a specific verb (lookup) and resource (one HTS code) and enumerates exactly what comes back: description, general/special/column 2 rates, Section 301 status, exclusions, and the 2026 reduction flag. The 'one HTS code' scoping plus 'search_hts' as a sibling makes the boundary between exact lookup and search immediately clear.

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 (4, 6, 8 or 10 digits)' implies this is the single-code path versus the sibling search_hts, but the description never explicitly says when to use this instead of search_hts, section301_lists, or china_deal_status. Usage must be inferred from the name and scope rather than stated.

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