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

With no annotations, the description carries the full behavioral burden. It usefully discloses authentication modes (API key, OAuth, x402 payment) and that results are "current" classifications, but says nothing about read-only nature, result ordering, or what a rate stack includes. That is helpful but incomplete for a no-annotation tool.

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 with the access constraint front-loaded and the core search behavior immediately after. The optional rate-stack clause is a useful qualifier rather than filler; little could be trimmed without losing meaning.

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, and the description never indicates the shape of results (e.g., codes plus descriptions plus rates) or how many results are returned. Given the domain complexity and absence of structured documentation, it leaves meaningful gaps, though the core call path is clear.

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 only 33%: query and limit are undocumented in the schema. The description compensates by explaining that the query accepts product descriptions, codes, or prefixes — non-obvious from a bare string — and clarifies that country triggers origin-specific rate stacks. It still doesn't explain the limit parameter or pagination behavior.

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 and resource ("Search current US HTS classifications") and clarifies the accepted query forms (product description, code, or prefix), which differentiates it from an exact-code tool like lookup_tariff. It never names a sibling tool explicitly, so the differentiation is implied rather than stated.

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 through the query forms the tool accepts (description text, code, prefix) and the optional country parameter for rate stacks, but there is no explicit when-to-use or when-not-to-use guidance relative to lookup_tariff, compare_tariff_codes, or search_rulings. An agent must infer the routing decision.

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