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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds behavioral context by specifying the ranking range (5-20), the impression threshold concept, and the CTR comparison criterion, which go beyond the annotations. It doesn't contradict annotations and provides useful execution details.

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 a single, well-structured sentence that front-loads the core criteria (rankings 5-20, impressions, CTR) and concludes with the actionable outcome. There is no fluff or redundant information; every clause 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 tool has 6 optional parameters and no output schema. The description explains the tool's purpose and criteria but does not describe the return format (e.g., whether it returns a list of keywords, URLs, or structured data). For a query tool that returns results, this omission is noticeable, though the name and purpose imply the nature of the output. Given the simplicity and read-only nature, it is adequate but not complete.

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 covers 100% of parameters with descriptive text, so the baseline is 3. The description does not add parameter-specific semantics beyond the schema; it mentions criteria like 'plenty of impressions' which loosely relate to min_impressions but without specific syntax or additional meaning. Since the schema already documents each parameter, the description's contribution here is minimal.

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 verb ('queries') and resource ('ranking 5-20 with plenty of impressions but a click-through rate below what is typical at their position'), and clearly frames the purpose as identifying where a title or snippet rewrite is worth the most clicks. This is precise and distinguishes it from siblings like find_cannibalization or page_queries, which address different optimization angles.

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 provides clear context on the intended use case—finding CTR improvement opportunities—but does not explicitly mention when not to use it or name alternative tools. It implies the usage scenario well, yet lacks explicit exclusions or sibling comparisons, so it falls short of a 5.

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