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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld). The description adds important context beyond annotations: the service is free, requires no authentication, and every answer must carry an Ahrefs attribution line shown with the numbers. It does not mention rate limits, but the added licensing/attribution requirement is a meaningful behavioral disclosure.

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 short sentences, front-loaded with the metric and scope, then the access conditions, then the required attribution. There is no wasted text; each clause carries practical information for invocation.

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 one parameter, full schema description coverage, an output schema, and rich annotations, the description supplies the remaining needed context: cost, auth, attribution requirement, and batch scope. Nothing essential for correct invocation 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 coverage is 100% with one documented domains parameter including examples and a maxItems constraint. The description repeats the batch limit and clarifies 'anyone's' domains, but adds no format or syntax details beyond the schema, so the baseline of 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?

The description states the exact metric (Ahrefs Domain Rating, 0–100), the batch scope (up to 25 domains), and that it works for any domain. This is specific and actionable, but it does not explicitly distinguish itself from siblings like check_domain or domain_age.

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?

It implies usage (look up ratings for any domains) and notes it is free and needs no sign-in, but it gives no explicit when-to-use guidance or alternatives. The agent must infer that this is the tool for rating scores rather than availability or age.

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