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

With no annotations, the description must carry the behavioral burden. It does disclose the paid nature ($0.001) and the WHOIS data source, which is useful, but it does not state read-only behavior, potential latency/failure, or how trust band is derived. This is adequate for a simple lookup but leaves clear gaps.

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 a single front-loaded sentence with no filler; it packs purpose, output fields, source, and price into minimal words. Every element earns its place.

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-required-parameter lookup with an output schema, the core call is just 'domain', so the description is minimally viable. It is incomplete on usage guidance and the optional agent_id, but the output schema covers return-value details and the complexity is low.

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 no parameter documentation and schema description coverage is 0%. The required 'domain' parameter is inferable from the tool purpose, but the optional 'agent_id' parameter is completely unexplained in both schema and description, and domain format requirements are not stated.

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 output: WHOIS creation date, age, and trust band, making the resource and purpose clear. It lacks an explicit verb but is unmistakably a domain-age lookup, and no sibling tool covers this domain. Full 5 is withheld because 'trust band' is undefined and the phrasing is a bare noun phrase.

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?

There is no statement of when to use this tool versus alternatives, no exclusions, and no comparison to the many ddg_* siblings. The only context is the implied scenario of needing domain creation/age/trust-band data, which is not enough guidance for tool selection.

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