ads_keyword_performance

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It implies a read-only performance report and defines the scope of data, but it does not explicitly state that it is non-mutating, how results are aggregated, or what happens when filters are omitted. The report-like nature is strongly implied, but some behavioral details remain implicit.

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 compact and front-loaded, with the data scope and metrics in the first line followed by a concise argument list. There is no filler or redundant repetition of schema information; every sentence adds useful signal.

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 that an output schema exists, the description does not need to explain return values, and it covers purpose, metrics, and all parameter semantics. The main remaining gap is the lack of explicit guidance comparing this to sibling reporting tools and clarifying the practical requirement of customer_id, but overall it is sufficient for an agent to invoke the tool correctly.

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?

The schema has zero description coverage, but the description compensates by explaining all four parameters: customer_id format, date_range as a GAQL constant, campaign_id as an optional filter, and limit as a cap. It does not clarify whether customer_id is practically required despite its nullable default, but the schema supplies the defaults.

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 identifies the tool as a keyword-level performance report by naming the exact metrics returned: text, match type, quality score, clicks, cost, conversions, and CPA. This distinguishes it from sibling tools like ads_campaign_performance, though it lacks an explicit action verb such as 'retrieve' or 'list'.

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 explicitly states a use case: 'Useful to find wasteful or high-performing keywords.' This gives an agent clear context for when to select this report, but it does not mention alternatives or exclusion conditions, so it falls just short of full routing guidance.

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