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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses important behavioral details: normalization to registrable domain, 24-hour caching, and a 60-lookups-per-hour rate limit. These details help the agent predict repeated-call behavior and throttling without contradicting annotations.

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 concise and front-loaded: the main purpose appears first, followed by scope, input behavior, caching, and rate limit. Every sentence carries useful information and there is no redundancy or filler.

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 single-parameter read-only tool with an output schema and strong annotations, the description is complete. It covers what the tool returns, which domains are in scope, how input is normalized, cache behavior, and rate limits. Nothing essential is missing for an agent to invoke it correctly.

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 already describes domain_or_url as a domain name or full URL, and schema coverage is 100%. The description adds meaningful semantic depth by explaining that subdomains and paths are reduced to the registrable domain, with a concrete example, which goes beyond the schema's basic description.

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 action and resource: returns Ahrefs Domain Rating (0-100 authority score) for any domain. It clearly differentiates the tool from siblings by emphasizing it works for competitors, prospects, and sites found in backlinks, not just the user's own websites.

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 provides clear usage context: it is for checking authority of any domain, including competitors and link-building prospects. It does not explicitly name alternative tools or state when not to use it, but the context is strong enough that an agent can infer appropriate scenarios.

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