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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so 'Read only' is redundant. 'Saved data' adds real context that these are stored snapshots rather than live figures, but freshness, the reporting window covered, and any staleness caveats are not disclosed.

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, front-loaded sentences with no filler and the metric list is where an agent needs it. The trailing 'Read only' clause is mildly duplicative of the readOnlyHint annotation, costing a bit of economy.

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?

For a one-parameter, annotation-covered read tool with no output schema, the description does the important work of enumerating return values and flagging the saved-data nature. It is slightly incomplete on the time window the saved results cover and any freshness expectation.

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 that brand_id comes from list_brands and that omitting it defaults to the most recently updated brand. The description adds nothing beyond that, which matches the baseline of 3 for full schema coverage.

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 (Get) and a narrowly scoped resource, then enumerates the exact fields returned (spend, revenue, ROAS, purchases, click rate, cost per click, frequency) plus the ROAS goal and gap. That enumeration is what separates it from siblings like get_sales_funnel, get_ad_fatigue or get_today.

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 or when-not-to-use guidance and no named alternative, despite heavy sibling overlap (get_sales_funnel, get_ad_fatigue, get_live_alerts). The only framing is a data trait ('Read only, saved data'), which is not usage routing.

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