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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered without the description. The description adds one useful behavioral fact — that results are aggregated across the merchant's products rather than per-product. However, it omits the time window the rates are computed over and whether the merchant must be authenticated/known, which materially affects interpretation of the numbers.

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?

One short sentence that front-loads the returned metrics with zero filler or repetition. It is appropriately sized for a simple read tool, though the fragment structure omits any orienting verb or scope clause.

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 the description is not obligated to explain return values, and the annotations cover the safety profile. For a one-parameter read tool this is minimally viable, but the absence of usage context and of any parameter guidance leaves real gaps.

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 0% and the single parameter shop_domain has only a regex pattern, no prose. The description never mentions the parameter, so it does not explain whether it accepts a bare domain, a full URL, or how a domain maps to a merchant. The self-descriptive name helps, but the description contributes nothing beyond 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 names the specific resource (a merchant's aggregate profile) and enumerates the exact metrics returned: return rate, complaint rate, delivery issue rate. This distinguishes it from sibling get_product_outcomes, which is product-scoped rather than merchant-scoped. It lacks an explicit verb ('retrieve'/'aggregate'), but the content is unambiguous.

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 tool versus compare_products, get_product_outcomes, or search_products. The merchant-level aggregation scope is implied by 'across a merchant's products' but never framed as the selection criterion, and no prerequisites or exclusions are given.

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