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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds one genuinely useful behavioral note — 'No personal data about viewers' — which clarifies the privacy scope of the returned data, but says nothing about freshness, aggregation windows, or cost.

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 short sentences with no filler, front-loaded with what the report contains. The first sentence is slightly cryptic as a fragment ('Days each screen confirmed showing the advert') and could be tightened, but nothing is wasted.

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 single parameter is fully covered. What is missing is the usage context that matters here — when to call this versus advertiser.bookings.get or list — leaving the definition adequate but not complete for disambiguation.

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 booking_id and its provenance (advertiser.bookings.create or bookings.list) are already documented. The description adds no parameter-level detail such as whether booking_id scopes to a single campaign/period, 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 makes clear what the tool produces: per-screen confirmation days plus estimated view counts (a proof-of-display report, matching the title). It is clear, but it never states an action verb and does not distinguish itself from advertiser.bookings.get, which an agent could easily confuse it with.

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 no when-to-use guidance, no prerequisites, and no mention of alternatives such as advertiser.bookings.get or advertiser.bookings.list. The only routing hint lives in the schema's booking_id description, not the tool description.

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