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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description's 'Read only, saved data' partly restates that, but the 'saved data' note usefully signals the figures are not live (contrasting with get_live_alerts). It adds no detail on pagination, freshness window, or failure behavior.

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 single dense sentence that front-loads the resource and enumerates returned metrics, with no filler. It is slightly packed ('frequency, click rate and its change, and hook rate per ad') but every clause carries information.

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 rich annotations, one optional fully-described parameter, and no output schema, the description supplies the one thing the schema cannot: what metrics come back and in what order. Adequate for invoking the tool correctly, though an explicit cue on when to reach for this versus get_performance would close the last gap.

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?

Only one parameter and schema description coverage is 100%, so the schema already explains brand_id and the 'most recently updated brand' default. The description adds no additional parameter meaning, which is acceptable at baseline 3.

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?

Names a specific resource (ads) and the exact condition being reported (fatigue, signaled by frequency, click rate change, hook rate), plus the sort order (highest frequency first). It is clearly distinct from siblings like get_performance or get_ad_copy_review, though it never names an alternative to contrast against.

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?

Usage is only implied — an agent infers it should call this when investigating ad wear-out. There is no explicit when-to-use statement, no mention of when to prefer get_performance instead, and no prerequisites beyond the optional brand_id.

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