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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful context beyond that: the call is free, it searches the 'current' schedule, and it returns 8/10-digit codes with descriptions and base MFN duty rates — no output schema exists, so this return-value disclosure carries real weight. It stops short of noting result ordering or the meaning of the limit cap.

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 short sentences, front-loaded with the key qualifier ("Free") and the search modes, with zero filler. Every sentence contributes either usage, scope, or return information.

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 supplies the return shape (code lengths, descriptions, MFN rates), which is the main completeness risk for this tool. The remaining gap is the undocumented limit parameter and the lack of routing guidance against the two siblings.

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 50%: query is documented in the schema and the description restates the same keyword/prefix distinction. The limit parameter (default 10, max 50) is unexplained in both places, so its meaning as a result cap must be guessed from the name.

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?

Names a specific verb (Search) and resource (US Harmonized Tariff Schedule), plus the two accepted query forms (keyword or code prefix). It does not explicitly differentiate itself from the sibling hts_lookup, so an agent must infer that lookup means exact-code retrieval rather than search.

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?

Usage is implied by "by keyword or code prefix" and the word "Free", which hints at a no-cost call. There is no explicit statement of when to prefer hts_search over hts_lookup or calculate_duty, and no prerequisites or exclusions are given.

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