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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context: billing occurs per call with data, results are capped at 100 keywords per call, and the output is sorted by estimated traffic with position distribution totals.

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 sentences, front-loaded with scope and return fields. Every sentence carries useful information: the first defines the resource and output columns, and the second adds the per-call limit and billing note.

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?

With no output schema, the description usefully enumerates the returned fields and mentions position distribution totals, billing, and the 100-keyword cap. It is sufficiently complete for an agent to decide and invoke, though it lacks details on empty-result behavior or whether results beyond 100 are accessible via pagination.

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%, and the schema already documents the domain, country, language, and limit parameters with defaults. The description reinforces that domain can be a URL and that results are scoped to one country, but it adds little parameter syntax or meaning beyond what the schema provides.

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 resource and scope: Google keywords a domain or URL ranks for in one country, sorted by estimated traffic. It clearly distinguishes this from keyword_metrics or google_serp by focusing on domain-ranking keywords, though it does not name sibling tools explicitly.

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?

There is no explicit guidance on when to use this tool versus alternatives like keyword_metrics, domain_overview, or google_serp. The usage is implied by the description, but no exclusions, prerequisites, or alternative-selection criteria are provided.

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