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

Annotations already establish readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description goes beyond them by disclosing the exact returned attributes, that IDs are stable, that timestamps are UTC ISO-8601 instants, and that no performance metrics are returned — genuinely useful behavioral context for a read tool.

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?

Two tight sentences, front-loaded with what is returned and immediately followed by the exclusion that matters most for query selection. No filler and nothing that restates the tool name.

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 input schema, full annotations, and an output schema, the remaining burden on the description is small, and it correctly covers scope and the metrics exclusion. The gap is routing guidance against the crowded query_advertising_* family, which would make this a complete definition.

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%, and every parameter (name, limit, offset, states, storeId, portfolioIds) carries its own documented semantics including the 100-item cap and the sellerId:marketplaceId store format. The description adds nothing about parameters, so the 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 gives a specific verb and resource ("Returns current Amazon Ads portfolios") and enumerates the exact fields returned, so an agent knows precisely what this tool produces. It also names a scope boundary ("management query ... does not return performance metrics"). It stops short of distinguishing itself from the many query_advertising_* siblings (campaigns, ad groups, targets), so it lands at 4 rather than 5.

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?

There is a single negative scoping hint ("does not return performance metrics"), but no statement of when to choose this over query_advertising_campaigns or the other query siblings, and no mention of the required storeId prerequisite or the synchronized-data caveat. An agent must infer selection from the name alone.

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