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

With no annotations, the description carries the full behavioral burden. It discloses a key trait: the response includes both visible rows and authoritative server summaries, and the latter should be trusted. But it doesn't mention whether the operation is read-only, any pagination limits, or what happens when scopes exceed 20, leaving many behavioral aspects undisclosed.

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 sentences with no fluff. The primary purpose is front-loaded, and the critical usage hint about server summaries is placed immediately after. Every word earns its place.

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 schema is complex with many optional parameters, enums, defaults, and nested objects, yet the description explains none of them. There is no output schema, no annotation, and no guidance on return format, permissions, or error cases. The description is far from sufficient for an agent to correctly invoke this tool.

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 description adds no meaning to any of the schema parameters. It only refers to 'scopes' generically without explaining the nested object structure, the meaning of group_by, view_mode, date_from/to, or any defaults. With schema description coverage at 0%, the description fails to compensate, leaving the agent to guess at the 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 clearly states it provides a 'ledger-backed insights overview' for up to 20 scopes, which identifies the verb and resource. The batch nature is implied by the name and the scope limit, but it doesn't explicitly contrast with sibling tools like google_ads_insights_overview_query, so it's clear but not fully differentiated.

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?

It gives one concrete usage instruction: 'Use server summaries instead of summing visible rows.' This tells the agent how to interpret the results. However, it doesn't state when to choose this batch tool over the single-scope alternatives, nor does it mention any exclusions or prerequisites.

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