Query WHOIS database for domain registration details. Returns registrant name, registrar, registration and expiration dates, registrant contact info, and nameserver list. Use for domain research, owner identification, or tracking registration status.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain name to look up in WHOIS (e.g. 'example.com', 'company.org') |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the read-only nature is known. The description adds useful detail about the returned data (registrant, registrar, dates, etc.), but does not disclose potential limitations like privacy redaction or rate limits. This is adequate but not richer than annotations alone.
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 that are concise and front-loaded: the first states the purpose, the second lists returned fields and use cases. No wasted words.
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?
With a single parameter, no output schema, and good annotations, the description sufficiently covers purpose, return contents, and use cases. It lacks caveats about WHOIS privacy or rate limits, but these are not essential for a simple query 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 input schema has 100% coverage with a clear description and example for the 'domain' parameter. The description does not add extra parameter-level detail beyond the schema, so the baseline of 3 applies.
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 clearly states the action ('Query WHOIS database') and resource ('domain registration details'), and lists specific return fields. It effectively differentiates from sibling tools like check_dns, check_ssl, crawl_website, and detect_tech_stack by focusing on WHOIS specifically.
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 explicit use cases ('domain research, owner identification, or tracking registration status'), offering clear context for when to use the tool. It does not explicitly name alternatives or exclusions, but the use cases sufficiently imply usage boundaries.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct aspect of web analysis: DNS records, SSL certificates, website crawling, technology detection, and WHOIS data. There is no overlap in purpose, so an agent can easily select the right tool.
All tool names follow a consistent verb_noun pattern: check_dns, check_ssl, crawl_website, detect_tech_stack, lookup_whois. The verbs and nouns are clear and consistently formatted with underscores.
Five tools is well within the ideal 3-15 range and each tool serves a distinct, necessary function for the server's stated purpose. The toolset feels cohesive and neither bloated nor sparse.
The toolset covers core web analysis domains: DNS, SSL, crawling, tech stack, and WHOIS. Minor gaps exist, such as missing page speed or robots.txt analysis, but these are not critical for basic SEO and web analysis workflows.