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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds that results are paged and cites the underlying endpoint, which is useful beyond the annotations, but it says nothing about behavior on an invalid product_id, empty results, or auth/rate-limit expectations.

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?

Three short fragments, front-loaded with the resource and its fields, then pagination, then endpoint. Nothing is padded, though the telegraphic style leaves it slightly under-written rather than over-written.

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 simple 3-parameter read tool with full schema coverage and explicit annotations, this is nearly sufficient. With no output schema, the field list in the description usefully stands in for return-shape documentation.

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%, and the schema already documents page, limit (1-250, default 50) and product_id in detail. The description adds no additional parameter meaning, so the 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 names the exact resource (the variants of one product) and enumerates the fields returned (size, color, SKU, barcode, price), which is more specific than the title alone. It does not explicitly contrast with sapo_get_product_variant (single variant) or sapo_list_products, so a reader must infer the list-vs-get distinction from the tool name.

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?

There is no statement of when to use this over sapo_get_product_variant or how it relates to sapo_get_product. The only usage signal is the embedded REST path and the required product_id, which implies 'fetch all variants for a known product' but never says so or names any alternative.

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