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

Annotations already declare readOnly, idempotent, non-destructive and openWorld behavior, so the safety profile is covered. The description adds that only public sites are accepted and that each result carries a grade plus top strengths/weaknesses, which is useful extra context. It doesn't mention cost, latency, or failure behavior for unreachable/private URLs.

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?

Two tightly written sentences, front-loaded with the operation and scope before the use case. Nothing is wasted or repeated.

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?

For a one-parameter, read-only tool, this is close to complete: the description covers the input scope, the ranking behavior, and the return payload, since there's no output schema. Minor gaps remain around error behavior and whether all URLs must be reachable.

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?

There is only one parameter and schema coverage is 100%, so the schema already documents the 2-5 domain/URL constraint. The description's '2-5 public websites' mostly restates the schema, adding only the 'public' qualifier, 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 pair (score, rank) plus the resource (2-5 public websites) and the output shape (grade plus strengths/weaknesses, side by side). This clearly separates it from get_visibility_score, which covers a single site, since comparability across 2-5 sites is stated 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?

'Use to benchmark a site against competitors and explain who wins and why' gives a clear usage context. It never names an alternative tool (e.g., get_visibility_score for a single site) or states when not to use it, 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.