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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds real value by disclosing a data-freshness caveat ('recent ~3 days may be incomplete') and by scoping what spend is and is not included, which is behavioral context not present in the annotations.

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 dense sentences that are front-loaded with the primary use case, followed by scope exclusions and then routing to alternatives. Every clause carries information, though the sentence packing is heavy and could be split for scannability.

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, return values need not be explained, and the description covers scope, freshness, and alternatives thoroughly. Minor gaps remain: no mention of the default 30-day window or pagination behavior, though both are fully specified 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 schema already documents all 11 parameters (asin, dates, sort_by, pagination, etc.). The description's mention of 'by campaign/ad group' and the metric list loosely maps to sort_by values but adds no syntax, default, or format detail beyond 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?

States a specific verb and resource: Sponsored Products advertised ASIN/SKU performance broken down by campaign/ad group, listing the exact metrics (spend, clicks, sales, ACOS, ROAS, same-SKU sales). It explicitly carves itself out from siblings like get_adgroup_performance and get_campaign_performance by naming the ASIN/SKU attribution scope.

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 explicit when-to-use ('use for Sponsored Products advertised ASIN/SKU performance'), an explicit exclusion ('not total ad spend for an ASIN or brand'), and names concrete alternatives with their conditions: get_sales_and_traffic/get_tacos for total organic+paid sales, get_purchased_products for post-click purchases. Nothing is left to inference.

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