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

With no annotations, the description carries the full burden. It discloses that the tool is ledger-backed, defaults to 20 visible rows, and that summary/total covers the full filtered scope. However, it does not state whether the operation is read-only, any rate limits, authentication needs, or clarify 'ledger-backed'.

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 extremely concise, with two sentences and no filler. The core purpose is front-loaded, and every word contributes value. This is ideal conciseness, even if the content is sparse.

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 16 parameters, no output schema, and no annotations, the description is far too sparse. It fails to specify what inputs are needed for a valid query, what the results look like, or how to control grouping, dates, and filtering. An agent could not use this tool correctly based on this alone.

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 only 6%, so the description must compensate for the undocumented parameters. It does not explain any of the 16 parameters, such as group_by, sort_key, date_from, date_to, search, or filters. 'One scope' offers only a vague hint and does not map to customer_id or other parameters.

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 identifies the tool as a ledger-backed insights overview for one scope and mentions default row limits and summary coverage. This is a clear purpose statement, but it does not explicitly distinguish it from sibling query tools like google_ads_insights_query_daily or google_ads_insights_overview_batch.

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?

There is no guidance on when to use this tool versus alternatives such as google_ads_insights_query_daily or google_ads_insights_overview_batch. It does not state the intended use case (e.g., high-level overview vs granular daily data) or any exclusions.

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