get_ad_unit_performance

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

With no annotations, the description must disclose behavioral traits such as read-only nature, required inputs, or filtering behavior. It only lists output metrics and does not mention that a date range is required, how 'per ad unit' is aggregated, or any potential side effects. The safety profile is entirely unaddressed.

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 a single, well-structured sentence that front-loads the core purpose and lists key metrics. Every word earns its place, with no redundancy or filler.

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?

The tool has 4 parameters and no output schema, so the description should clarify the return structure and key inputs. It lists the metrics but does not mention that date_range is required, how results are grouped, or whether ad_client_id filtering is available. The schema covers inputs, but the absence of usage and behavioral context makes it only adequate.

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 coverage is 100%, so the baseline is 3. The description adds the list of metrics but does not add meaning to the parameters beyond what the schema already provides (e.g., date range, ad_client_id). The description is not needed for param understanding.

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 the tool's purpose: 'Get performance metrics per ad unit' with a specific list of metrics (CTR, RPM, impressions, clicks, earnings). This distinguishes it from sibling tools like get_earnings_summary or get_top_pages by focusing on ad-unit-level performance.

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 no guidance on when to use this tool versus the sibling tools. It does not mention alternatives or exclusions, leaving the agent to infer usage solely from the name and description.

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