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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds two useful traits beyond that: results are 'bounded' (a cap on output) and 'hot-cached' (latency/freshness behavior). It still omits rate limits, auth requirements, and what happens with the connection_context token.

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 tight sentences, front-loaded with the action and resource, with no filler. It is well sized; the only minor issue is that the second sentence bundles two distinct traits without elaboration.

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 an 8-parameter tool with 13% schema coverage and no output schema, the description is too thin. It gives no sibling routing, no parameter meaning for six of eight inputs, and no indication of the shape or volume of the returned ideas.

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 13% (only customer_id is documented), so the description must carry the load and it does not. 'Bounded' loosely maps to limit and 'one owned customer' to customer_id, but url, keywords, language_id, geo_target_ids, network, and the mctx_v1 connection_context pattern are all left unexplained.

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?

States a specific verb (Generate), resource (keyword ideas) and scope (Google Search, historical metrics, one owned customer). It is clearer than a bare name, but it never distinguishes itself from close siblings like google_ads_keyword_themes or google_ads_keyword_historical_metrics, which an agent must choose between.

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 'for one owned customer' is a constraint, not usage guidance. There is no statement of when to pick this over google_ads_keyword_themes, keyword_historical_metrics, or keyword_forecast_metrics, and no prerequisites for the customer_id or connection_context.

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