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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the pagination cap (up to 20 per page) and 1-indexing, but the 20-per-page fact is already repeated in the schema, so net new behavioral context is thin.

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 tight sentences with the core action front-loaded and the parameter guidance trailing. Every clause carries information and nothing is padded.

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?

An output schema exists, so return values need no explanation, and the description covers scope, pagination, and parameter provenance. For a simple read-only, two-parameter tool this is essentially complete, with only minor gaps like rate limits.

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 both parameters are fully documented in the schema. The description restates that product_id is numeric and from aliexpress_search and that page is 1-indexed, adding no format or meaning beyond what the schema already provides, 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 verb (Fetch), resource (public AliExpress product reviews and rating statistics), and scope (one page of up to 20). It clearly distinguishes itself from the sibling aliexpress_search by naming it as the source of the product_id rather than as an alternative for the same 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?

It tells the agent the prerequisite for the required parameter (a numeric product_id returned by aliexpress_search) and the indexing convention for page. It gives clear context but does not explicitly state when-not to use this tool or name a competing sibling for review data.

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