hts_lookup

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

Annotations include readOnlyHint and openWorldHint, but the description goes well beyond them. It discloses critical behavioral nuances: duty rates are authoritative verbatim text and never coerced to numbers; empty Special equals no special rate; hierarchy inheritance rules; additional duties often ride Chapter-99 rows; completeness guarantees about arrays and offset behavior; and explicit error-handling protocol (schema_drift THROW, upstream_unavailable). This adds substantial context beyond annotations with no contradictions.

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 comprehensive but extremely long, running into two dense paragraphs with multiple bolded subsections. While every sentence carries valuable information, the sheer length exceeds what is necessary for a typical tool definition. It is front-loaded with purpose, but the extensive use of ★ headers and repeated warnings makes it less concise than ideal. It is not a tautology, but it could be trimmed without losing essential guidance.

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 carries the full burden of explaining the return structure, which it does exhaustively: it lists all fields of the `lines` array, explains the honesty guarantees, and covers error handling, pagination, and disclaimers. For a complex tool with 3 params and no output schema, this is as complete as an agent could need.

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 description coverage is 100%, so the baseline is 3. The description adds some semantic details beyond the schema (e.g., 'both ride the keyword= search', client-side pagination, and >3 char requirement), but these are also largely reflected in the schema's own parameter descriptions. The added value is marginal and does not significantly enhance understanding beyond what the schema already provides.

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 begins with a specific verb and resource ('Look up US import-tariff classification + duty rates from the USITC Harmonized Tariff Schedule') and immediately clarifies the dual-mode query (KEYWORD or HTS number). It distinguishes itself from any potential sibling by being uniquely tied to USITC tariff data, and the resource and action are unambiguous.

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 explicitly states when not to use this tool ('NOT a binding CBP ruling or landed-cost quote') and directs the agent to an alternative ('confirm via CBP (CROSS/eRulings)'). It also explains the scope and limitations, providing clear context for when this tool is appropriate versus when to consult other sources. This covers both when and when-not clearly.

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