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

Annotations already establish that this is a read-only, idempotent, non-destructive operation. Beyond that, the description adds meaningful behavioral rules: flow=both must use balance, and order=asc surfaces the largest deficits. It does not cover pagination or return-shape behavior, but the annotations lower the burden.

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?

The English portion is concise and front-loaded, starting with the core resource and then giving the key combination rules. The bilingual duplication doubles the length, but each version serves a distinct audience and neither contains filler.

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 9-parameter ranking tool with no output schema, the description covers the most important semantic constraints around flow, by, order, and country. It relies on the fully documented schema for the remaining parameters, which is reasonable, though it could say more about what the ranked response contains.

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 3. The description adds useful cross-parameter semantics not fully captured by the schema: export/import pair with value or yoy, both pairs with balance, and country scopes the ranking to trade with one partner. It does not explain level, month, limit, or lang, but those are well documented 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?

The description clearly states that this returns an item ranking and immediately specifies the valid flow/by combinations, which gives the agent a concrete sense of the tool's output. It does not explicitly differentiate itself from siblings such as get_item_summary or get_partners, keeping it from a 5.

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 description gives conditional guidance for parameter combinations (export/import with value or yoy; both with balance and order=asc). However, it does not state when to prefer this tool over sibling tools like get_item_summary, get_partners, or get_series, so usage against alternatives is only implied.

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