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

Beyond the annotations (which already declare readOnly/idempotent/non-destructive), it discloses two high-value traits: rows are passed through in Amazon's own field names unchanged (no normalization contract), and an EMPTY week means no rows returned rather than zero traffic — a real interpretation hazard. It also states the brand-registration prerequisite.

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 what the tool returns, then the caveat about raw field names, then empty-week semantics, then use cases — a sensible order. Slightly dense in the opening clause, but every sentence carries information.

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 carries the return-value burden and does so by enumerating the metric families (impressions, clicks, add-to-carts, purchases, share vs. all of Amazon) and the raw-field-name contract. Missing any note on coverage limits, date-range control, or pagination, which an agent would want before calling.

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 each parameter is already documented in the schema. The description only adds the implicit 'per ASIN per week' framing; it says nothing about how account or marketplace_id interact with the optional asin filter.

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 a specific verb and resource (Brand Analytics Search Query Performance) plus granularity (per ASIN per week) and audience restriction (brand-registered sellers). It does not name a sibling to contrast with — e.g. get_brand_search_terms or get_ads_search_terms — so the agent must infer the boundary itself.

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?

Gives two concrete motivating questions ('which searches find my product', 'where do I lose buyers between click and purchase') that tell the agent when this tool is the right pick. It stops short of explicit exclusions or naming the alternative tool for adjacent questions.

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