Get Ad Group Performance

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

readOnlyHint=true in annotations already establishes this as a safe read. The description adds the output sorting behavior ('Ordered by cost'), which is a genuine trait beyond the annotation, but says nothing about time-range defaults, auth requirements, or rate limits.

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, zero waste, with the resource scope front-loaded and the metric list and ordering compactly attached. Nothing extraneous, though it is not richly informative either.

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?

An output schema exists, so return-value structure need not be described, and the description still adds the metric list and sort order. With full schema coverage and a read-only annotation, the remaining gap is only the absent usage/alternative guidance.

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 all five parameters (customer_id, date_range, start_date, end_date, campaign_id) are already documented in the schema. The description adds no parameter-level meaning, which is the expected baseline when the schema does the heavy lifting.

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+resource ('Ad-group-level performance report') and enumerates the metrics returned, so the agent knows exactly what this tool produces. The 'ad-group-level' scope inherently distinguishes it from get_campaign_performance and get_keyword_performance siblings, though it never names them.

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?

No when-to-use, when-not-to-use, or alternative routing is given. The agent must infer from the name alone that this is the ad-group granularity counterpart to the campaign and keyword reports. 'Ordered by cost' describes output, not usage.

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