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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is known. The description adds the data fields returned but does not provide additional behavioral context such as pagination, rate limits, or error conditions. It neither contradicts annotations nor adds significant behavioral insight beyond them.

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 sentence states the core function clearly, and the second adds a related-tool pointer. No filler or redundancy; 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?

Given the presence of a full output schema and annotations, the description is sufficient for a simple lookup tool. It covers the primary return data, mentions a related tool for alternative use cases, and avoids needing to explain return structure. It is complete for its complexity level.

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 100%, so the schema fully documents both 'keyword' and 'country', including the country enum and default. The description does not add extra parameter semantics beyond mentioning 'keyword' as the central input, which is already obvious from the schema and tool name.

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 the tool returns search-volume, CPC, and competition data for a keyword, using a specific verb and resource. It also distinguishes itself from the sibling tool keywords_trends by naming it as related, clarifying the scope.

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 description gives a hint about related tool keywords_trends, implying an alternative exists, but it does not explicitly state when to use this tool versus the alternative. The usage context is only implied, not clearly defined.

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