get_ad_performance

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the tool is known to be safe. The description adds behavioral context by explaining the compact mode: it returns totals, top-10 ads with counts, and findings, and notes the size reduction (~90% smaller). This goes beyond annotations.

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?

The description is concise (three sentences) and front-loaded: first sentence states purpose, second lists return fields, third details compact mode. No redundant information, though the list of return fields could be integrated into the first sentence minimally.

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?

Given the output schema exists, the description covers return values adequately. It also details compact mode behavior. However, it lacks documentation for three parameters and does not differentiate well from sibling tools (e.g., get_asset_performance) in the context of comprehensive performance analysis.

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?

With 0% schema description coverage, the description must compensate. It only explains the 'compact' parameter and its effect. The remaining three parameters (customer_id, date_range_end, date_range_start) are not described at all, leaving the agent without guidance on their usage or format.

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 clearly states 'Get ad-level performance data' which is a specific verb+resource. It lists the fields returned, distinguishing it from other performance tools like get_campaign_performance or get_keyword_performance. However, it doesn't explicitly differentiate from sibling tools like get_asset_performance, leaving some ambiguity.

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 description provides guidance on when to use compact=true ('for audits/overviews') and the benefits. However, it does not specify when to avoid the tool or mention alternatives among siblings, such as get_ad_performance vs get_detailed_asset_performance.

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