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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds meaningful behavior beyond that: the deterministic funnel_stage label set and its enum values, and an explicit statement of what is NOT returned (ad spend/ACOS, ad-triggering search terms). It does not mention any auth or rate-limit constraints, so it is not a full 5.

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?

A dense but front-loaded paragraph that leads with what is returned, then the use case, then the exclusions. Every sentence carries information, though the metric enumeration is verbose relative to the rest.

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?

Given an output schema exists, return values need not be spelled out, yet the description adds funnel_stage semantics and explicit exclusions. For an 11-parameter analytics tool this is complete, with only minor gaps around pagination/diagnostic behavior that the schema already hints at (include_diagnostics, next_offset).

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 (filters, pagination, sort columns, date range). The description focuses on returned fields rather than parameter meaning, so it neither adds to nor compensates for the schema. 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 and resource (returns Brand Analytics SQP weekly market search query volume plus the ASIN's per-query funnel) and enumerates the exact metrics returned. It also distinguishes itself from siblings by name, routing ads search-term needs to get_search_terms/get_keyword_performance.

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 an explicit when-to-use case ('to tell no impressions apart from impressions but no clicks for a query/ASIN') and explicitly names the alternatives for the data this tool excludes. An agent knows both when to pick it and when to pick something else.

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