whois

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

With no annotations provided, the description carries the full behavioral burden. It discloses important traits beyond a bare description: the return fields, clean JSON output, no raw WHOIS parsing, major TLD coverage, cost per call, and p99 latency. It does not cover authentication or rate limits, but it is substantially informative.

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 front-loaded with the core purpose and then efficiently lists return values, output cleanliness, TLD coverage, cost, and latency. Every sentence adds useful information with no wasted wording.

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?

There is no output schema, and the description compensates by listing the exact return fields and clarifying JSON format. For a simple one-parameter lookup tool with no annotations, this provides enough context for an agent to understand what it will receive and what the call costs.

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 description coverage is 100%; the single 'domain' parameter is fully documented in the schema with examples and formatting guidance. The description does not add parameter-level meaning beyond what the schema already provides, so the baseline of 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 a specific verb and resource: 'WHOIS Lookup — Domain registration lookup via RDAP (modern WHOIS).' It clearly distinguishes itself from generic DNS or SSL tools by focusing on registration data, but it does not explicitly name alternatives such as dns_lookup or domain_check.

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?

Usage is implied by the tool name and the phrase 'Domain registration lookup,' but there is no explicit guidance on when to use this tool versus sibling tools like domain_check or dns_lookup. No conditions, exclusions, or alternatives are provided.

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