whois

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

No annotations are provided, so the description is the sole source of behavioral disclosure. It notes the tool is read-only ('lookup') and analytics-only, but does not disclose potential limitations like data freshness, rate limits, or how errors are handled. It adds some context but lacks comprehensive transparency.

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 concise sentence with no fluff. It front-loads the purpose and includes essential details (returned fields, usage context) without redundancy, achieving maximum clarity per word.

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 tool with one parameter and no output schema, the description is quite complete: it lists expected return fields, indicates the use case (fraud-signal helper), and warns against misuse (not clearance). It could mention error behavior or data source reliability, but these are minor for a simple lookup tool.

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 schema description covers the sole parameter (domain name) fully, including an example. The description does not add any additional semantic detail beyond what the schema already provides, so a baseline 3 is appropriate.

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 'WHOIS/RDAP domain lookup' with specific verb and resource, and lists the key outputs (registration, registrar, age_days, status, nameservers). This clearly distinguishes it from siblings like dns, tls, and encode, making the tool's purpose immediately obvious.

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 context ('analytics-only fraud-signal helper') and an exclusion ('not clearance'), which helps the agent understand when it is appropriate to use. However, it does not explicitly mention alternative tools or contrast with siblings, so it falls short of full guidance.

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