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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely non-annotated behavior: product fields are populated only for report_type=PRODUCTS while PERFORMANCE rows can leave them null, which tells the agent what to expect in the response shape. It stops short of addressing pagination or auth, but adds real value beyond the structured fields.

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?

Three tight sentences, all front-loaded: purpose first, then the report_type nuance, then the exclusion/routing. No filler or restated title 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 an output schema present and 100% schema coverage, the description need not explain returns or parameter formats, and for a read-only list tool it covers scope, exclusions, and a key report_type behavior. Only minor gaps (pagination behavior, the compact vs raw row distinction) remain, and those are already in the schema.

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 baseline is 3 and the schema already documents all 17 parameters including range, defaults, and enum values. The description's mention of product_asin/product_name/brand_name/marketplace refers mainly to report_type-dependent output fields rather than adding syntax or constraint meaning 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 a specific verb/resource domain (Amazon Attribution tagged off-Amazon traffic) and enumerates the metrics it returns (purchases, sales, brand halo, new-to-brand), which is far more than the title 'Attribution performance' conveys. It also distinguishes itself from on-Amazon ad and seller-sales tools, so the agent can identify it without opening the schema.

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?

Explicit when-to-use ('Amazon Attribution tagged off-Amazon traffic') and explicit when-not ('Do not use for on-Amazon ads, search terms, or total seller sales'), with a routing hint toward campaign/search/sales tools. This is the clearest form of sibling disambiguation.

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