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

Annotations already declare read-only, idempotent, non-destructive, closed-world, so the bar is lower; the description still adds real context beyond them: free but rate-limited, and the important behavioral fork that product-only requests return a lookup link instead of a number. Missing output structure is partly compensated by naming the returned fields.

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?

Content is front-loaded and the key constraint (hts_code required for a number) appears early, but the entire description is duplicated in Chinese, roughly doubling length without adding information. The English half alone would score higher.

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 does list return components (duty lines, fees, totals, tax-date notes) and a top_3 field, which helps. However, three input parameters and their effect on the estimate (freight, origin, mode) are never explained, leaving gaps for a 7-parameter pricing 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 description coverage is 0% across 7 parameters, so the description carries the burden; it explains hts_code vs product and gives meaning to fob_usd/quantity, but leaves origin, freight_usd, and mode entirely undocumented anywhere. Partial compensation only.

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+resource ('Estimate landed cost') and spells out the inputs (hts_code/product, fob_usd, quantity) and outputs (duty lines, fees, total/per-unit cents, tax-date notes). It is clear what the tool produces, though it does not name or contrast any sibling tool.

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?

Gives concrete usage rules: pass hts_code to get a numeric calculation, product-only yields a lookup link rather than a number, and top_3 should be shown to the user first. It also notes free/rate-limited. It stops short of pointing at alternative tools when a calculation is impossible.

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