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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds meaningful non-annotation context: "Best-effort" (results may be incomplete or fail) and "Needs sign-in" (authentication requirement), which an agent must know before invoking.

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?

Front-loaded with purpose, then the payload list, then two short imperatives and two terse caveats. It is dense but every clause carries information; only the long enumeration makes it slightly run-on.

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 fully describes the return payload (prices, shipping, discounts, seller ratings, links, images, reviews). Combined with the sign-in and best-effort caveats and readOnly annotations, an agent has everything needed to call it correctly and interpret 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 description coverage is 100% and the schema already states that query and product_id come from search_products and that country must match. The description reinforces the same constraint but adds no new syntax, format, or fallback semantics, 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?

States exactly what it does for a single product from search_products and enumerates the returned data (per-seller price, total with shipping, discount, stock/delivery, seller rating, direct link, plus images, rating breakdown, features, reviews). An agent can instantly distinguish it from the sibling search_products, which searches across products rather than detailing one.

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?

"For one product from search_products" and "Use the same query and country as the search" give a clear precondition and the tool that must run first. It does not, however, state what to do if the product is missing from results or name any alternative tool for a different need.

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