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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuine context beyond that: results reflect 'current' state, ad IDs are stable, timestamps are Amazon createdAt/updatedAt as UTC ISO-8601, and the output feeds a specific downstream mutation tool. It stays silent on result-set size/pagination behavior, which keeps it from a 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?

Two dense sentences with the core purpose front-loaded and no filler. The long enumeration of return fields overlaps with the existing output schema, so it is slightly less economical than it could be, but every listed item still carries distinguishing meaning.

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 annotations, full schema coverage, and an output schema, the description covers purpose, scope, return semantics, and the downstream mutation path. The remaining gap is filter/pagination behavior over potentially large ad sets, which an agent would have to infer from the schema alone.

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 filters (states, campaignIds, adGroupIds, limit, offset) are fully documented in the schema. The description adds no semantics about filtering, combination rules, or default behavior beyond what the schema already provides — baseline 3 is appropriate.

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+resource (returns Sponsored Products/Display/Brands ads) and enumerates the returned identity fields, which cleanly separates it from query_advertising_campaigns, query_advertising_ad_groups, and query_advertising_targets. It never names those siblings explicitly, so the differentiation is inferred from the resource noun rather than stated.

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?

The second sentence gives a forward path ('Results can proceed to AD_AD_CHANGE for confirmed ENABLED/PAUSED state changes'), which implies the tool is the read step before a mutation. However, there is no guidance on when to use this versus query_advertising, query_advertising_campaigns, or how to narrow with the available filters — usage is implied rather than stated.

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