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

The annotation readOnlyHint=true already indicates a safe read operation. The description adds useful context such as 'free' and 'no-signup' requirements, which are not in the annotations, and clarifies that it accesses existing rankings rather than making changes. This adds value beyond the structured data.

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 that front-load the main purpose and quickly add use-case context. Every sentence earns its place with no redundant jargon, making it highly efficient.

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 a simple one-parameter read-only tool and no output schema, the description fully covers what the tool returns (queries, search volume, traffic) and the free/no-signup nature. It gives enough context for the agent to choose and invoke the tool correctly without missing critical details.

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 the single parameter (domain) with a clear description 'A domain, e.g. example.com'. The tool description adds no additional meaning about the parameter, so the baseline of 3 for high schema coverage 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?

The description clearly states what the tool does: it provides a free, no-signup SEO snapshot for any domain, listing queries ranked on page 1-2 with search volume and estimated traffic. This specific verb+resource (snapshot for domain) distinctly differentiates it from sibling SEO tools like keyword generators or content checkers.

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 says 'Great first look before signing up,' which clearly indicates the primary use case as an initial free assessment. It implies when to use it but does not explicitly name alternatives or exclusion scenarios, so it stops short of a perfect 5.

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