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

Annotations already cover safety and world assumptions, but the description adds material context they cannot: per-call cost (~$0.05), that it is one request regardless of domain, that the data comes from a proprietary Google index which lags a live SERP, and that results are not device-specific. It even frames the disclosure obligation when publishing the numbers.

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?

Three sentences, front-loaded with the core payoff (keywords plus volume and position, one request, any domain). Every sentence carries information, though the capitalised 'ONE' and the cost/pitch framing are slightly promotional for a tool definition.

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 does indicate the return shape at a high level (keywords with search volume and position) and covers cost, source, and freshness caveats. It stops short of describing output structure or size limits in detail, but nothing critical for a correct call is missing.

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 already documents domain, limit (with the 200-500 guidance and 'still one request'), and location codes. The description reinforces the one-request-per-call economics but adds no parameter syntax beyond what the schema provides, so the baseline 3 applies.

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 and resource: every keyword a domain ranks for, with search volume and position. It also scopes the tool apart from siblings by noting it works for any domain including competitors you do not own, so an agent can distinguish it from ownership-bound tools like get_gsc_queries or competitor-overlap tools.

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?

Gives a concrete when-to-use context (onboarding or pilot reports, run for client plus shortlisted competitors, then diff), which is strong situational guidance. It does not name alternative sibling tools or state exclusions, so it stops 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.