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

With no annotations, the description carries the full burden. It discloses the data source and that figures are finalized monthly, plus the x402 payment requirement and price, which is genuinely useful. However, it never states permissions, whether results are cached, error behavior for invalid prefixes, or latency/rate characteristics of a paid endpoint — a significant gap for a metered 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?

One dense, front-loaded block covering trigger, data, inputs, outputs, example, and price — every clause carries information. The final price/example sentence is slightly crowded and breaks the input/output rhythm, keeping it just short of ideal.

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 must explain return values, and it does: JSON totals in USD (exports FOB, imports CIF, balance, kg) plus 10-digit HSK lines with English descriptions and YoY percentages. Combined with the worked example, an agent has everything needed to call and interpret it.

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 100%, so the baseline is already 3, and the description adds real value on top: it enumerates the sort values (exports, imports, balance, total) and the default latest month, neither of which the schema spells out. It still doesn't clarify the number-or-string union on limit, but that is a minor omission.

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 and resource — monthly Korean trade by HS code — with concrete HS prefixes as examples (8542, 870323, 2710). The agent can immediately tell this apart from the sibling flash estimators kr_trade_exports_10day and kr_trade_pulse because the title and description anchor on finalized monthly Customs data.

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?

Opens with an explicit trigger: 'Use when you need South Korea's monthly trade for a product by HS code.' That is a clear usage context, but it never states when NOT to use it or names an alternative for flash/10-day estimates, so routing against siblings is only implied.

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