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

Annotations already declare the full safety profile (readOnly, non-destructive, closed-world), so the bar is lower. The description adds the ASIN-grain scope and the facts-only/deterministic-filtering stance and the default window, but the window default is duplicated in the schema and no pagination or return-shape behavior is added (and an output schema exists).

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-loads the resource and grain before the field enumeration, then closes with scope and the default window. The dense metric list is informative but slightly heavy; overall it is tight with little wasted text.

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 a full schema, output schema, and safety annotations, the description supplies what is missing: the ASIN grain, the default reporting window, and the 'facts only, no recommendations' scope. It is essentially complete for an agent to call it correctly.

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 all 11 parameters including defaults, ranges, enum values, and the pagination instruction. The description contributes only the shared ASIN-grain/window framing and no per-parameter detail beyond the schema, 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?

Specific verb (Return) plus resource (Amazon Brand Analytics Search Catalog Performance facts at ASIN grain) with an enumerated field list, so the resource is unambiguous. It partially differentiates from siblings via 'does not recommend actions', but it never names the adjacent tools (get_search_query_performance, get_brand_search_terms) an agent must choose between.

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?

The clause 'reports Amazon facts and deterministic filtering only; it does not recommend actions' establishes a when-not boundary, and the default Sun-Sat window is stated. However, there is no explicit guidance on when to pick this over the other search/catalog performance siblings, so usage is only implied.

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