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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds useful behavior beyond annotations by stating that results are returned as raw JSON rows, which matters because no output schema exists.

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 tight sentences with no wasted wording. The primary action and fallback scope are front-loaded, followed by the return format.

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?

For a flexible query tool with fully documented parameters and annotations covering safety, the description is largely complete. It states the return format but, without an output schema, does not describe the shape of returned rows in detail; this is a minor gap rather than a blocking omission.

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 input schema has 100% description coverage for all three parameters, including query syntax and limit default. The description adds no additional parameter semantics, so the baseline score of 3 is appropriate when the schema does the work.

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 states a specific operation: running a read-only GAQL SELECT query. It also clearly positions the tool as a fallback for reads not covered by the other Google Ads read tools, so an agent can distinguish it from siblings like google_ads_insights or google_ads_list_campaigns.

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 phrase 'anything the other read tools don't cover' gives clear guidance to use this only when a dedicated read tool is insufficient. It does not explicitly name the preferred alternatives or state when not to use it, but the fallback intent is unambiguous.

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