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

Annotations already cover the safety profile (read-only, idempotent, non-destructive, closed-world), so the description only needs to add scope context. It adds that multiple metrics are returned in a single call and that results are scoped to one country, which helps an agent anticipate a multi-metric payload. It does not mention freshness or units, which is a minor residual gap.

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 sentences, front-loaded with the use case and followed by the routing alternative, with no filler. The bilingual mirroring is deliberate given the ja/en lang parameter, so duplication earns its place.

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 read-only, four-parameter tool with a fully documented schema, the description covers purpose, usage routing, and output scope. No output schema exists, but the metric list in the description effectively communicates the shape of the result.

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% with enum and pattern constraints already documented, so baseline is 3. The description only implies the country scoping and says nothing about month, window, or lang beyond what the schema states.

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?

Names a specific resource and enumerates exactly what the response contains (exports, imports, balance, YoY, main items) for one country. Explicitly distinguishes itself from get_partners, a named sibling, so an agent can route without opening schemas.

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?

States the when ('want the overall picture for one country in one call') and the counter-case with the alternative to pick instead ('for one item's breakdown by partner, use get_partners'). That is an explicit when/when-not/alternative pattern.

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