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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description still adds real behavioral context: an availability filter is applied and, when nothing passes it, resultMode becomes 'fallback' and rows are the unconfirmed published order. That is exactly the non-obvious edge case an agent would otherwise misread as confirmed data. It does not mention ordering stability or what limit truncation does to the response.

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, both earning their place: the first establishes the return semantics, the second front-loads the fallback edge case. No redundancy with the title or schema, and no 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?

With no output schema, the description carries the burden of explaining return values, and it does so by naming score, rank, order, and the resultMode fallback state. Coverage is nearly complete for a three-parameter read tool; only the relationship to get_ranking and pagination behavior are left unspecified.

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 100%, so the schema already documents category, country, and limit including defaults and the ISO pattern. The description adds the notion of a country availability filter being applied, but does not explain the limit parameter or how truncation interacts with rank values, so baseline 3 applies.

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 states a specific resource and scope: a category's products as seen by a reader in one country, returned in order with published score and rank. It is clear what the tool returns, but it never names or contrasts with the sibling get_ranking, so an agent must infer the difference between the country-scoped and unscoped variants.

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?

Usage is only implied — 'as a reader in one country sees them' signals that this is the country-specific view, which hints at when to prefer it over get_ranking, but no explicit when-to-use, when-not, or alternative is named. There are no stated prerequisites either, such as needing a category id from list_categories.

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