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

Without annotations, the description carries the full burden. It discloses that data is 'live' and 'assembled from public protocol endpoints on our servers', implying a read-only lookup from public sources, but it omits details like rate limits, error behavior, or whether any authentication is needed.

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 sentences efficiently front-load the purpose and then list use cases. The first sentence is dense but still readable, and no sentence is wasted.

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 lookup tool with no output schema and no annotations, the description adequately conveys what data will be returned (DNS records and RDAP fields). It lacks error-handling or response-format details, but those are secondary for a straightforward read operation.

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?

With one parameter and 0% schema description coverage, the description only implies the input is a domain through the term 'domain' but gives no format guidance (e.g., whether to include protocol, subdomains, or an example). It barely compensates for the schema gap.

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 verb ('lookup') and resource ('domain') and lists exactly what is returned (DNS record types and RDAP fields). It distinguishes itself from most siblings by focusing on domain DNS/registration data, though it does not explicitly contrast with ssl-check or email-verify.

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 provides clear use-case contexts ('domain due diligence, phishing-site checks, counterparty infrastructure review and integration pre-checks') but does not specify when to avoid it or name alternative tools for overlapping tasks.

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