google_ads_campaign_performance

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

The annotations already declare this as a read-only, non-destructive, open-world operation. The description adds useful context about exactly which metrics are returned and the GAQL date-range semantics. It does not explain the effect of `include_paused` or how `customer_id` versus `login_customer_id` is used, leaving some behavioral gaps for a reporting tool.

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 two concise sentences: the first front-loads what the tool returns, and the second provides concrete date-range examples. It is efficient and appropriately sized, though it could briefly mention the other parameters.

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 values need not be explained, and annotations cover safety. However, three of four parameters lack any explanation, and the description does not cover how account selection or paused campaigns affect results. It is minimally complete but has clear gaps for an agent to call it confidently.

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 0%, so the description must carry the burden for all four parameters. It only explains `date_range` (with helpful GAQL values), while `customer_id` (required), `include_paused`, and `login_customer_id` are left completely undocumented. This is a significant gap given four parameters and no schema descriptions.

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 it returns campaign-level performance metrics (spend, clicks, impressions, conversions, CPA, ROAS) over a date range. The resource and scope are specific. It does not explicitly differentiate itself from the generic `google_ads_query` sibling, but the metric-focused framing makes its purpose distinguishable.

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 date_range examples (TODAY, LAST_7_DAYS, etc.) provide implied usage guidance for that parameter. However, there is no explicit guidance on when to use this tool versus `google_ads_query` or other reporting siblings, nor any note on prerequisites such as account access.

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