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

With no annotations, the description carries the full disclosure burden. It usefully names the returned fields (base rate, 2026 China-stacked rate, EU rate), but says nothing about data source, currency/freshness, auth requirements, or whether coverage is limited to US imports.

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?

Two tight sentences with the primary action and inputs front-loaded and the output contents second. Nothing is redundant or 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?

For a one-parameter read-only lookup with no output schema, the description supplies the essentials: what goes in, what comes back. It stops short of noting rate-basis caveats or data vintage, but nothing critical to invoking it correctly is missing.

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 schema already documents the single parameter at 100% coverage, so the baseline is 3. The description exceeds that by giving concrete examples of both accepted input shapes — a dotted HS code and a plain-language keyword — clarifying the ambiguous 'either/or' in the schema.

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 (look up) and resource (US import tariff rates) along with the accepted identifier forms (HS code or product keyword). It is unmistakably distinct from a generic tariff tool, though it never explicitly contrasts itself with the sibling tariff_export.

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 examples ('8703.24', 'laptop') imply how to invoke it, but there is no statement of when to use this rather than the sibling tariff_export, nor any prerequisites or exclusions. Usage is inferable but not guided.

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