Perform DNS lookup to retrieve DNS record details for a domain. Returns A records (IP addresses), MX records (mail servers), CNAME records, NS records (nameservers), and TXT records. Use for email setup verification, DNS troubleshooting, or server infrastructure research.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain name to look up (e.g. 'google.com', 'example.org', 'subdomain.example.com') |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=true, and the description adds that the tool returns A, MX, CNAME, NS, and TXT record details, giving the agent an accurate picture of the output. It doesn't mention rate limits or failure modes, but for a simple read-only DNS lookup, the provided context is sufficient.
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: the first states the action, the second lists use cases. No wasted words, key information front-loaded.
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?
A single-parameter read-only tool with no output schema; the description sufficiently covers what the tool does, what it returns, and when to use it. No major gaps.
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 already fully documents the 'domain' parameter with examples (100% coverage). The description adds no additional parameter-level detail, so it meets the baseline of 3.
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 'Perform DNS lookup' and a resource 'domain', and enumerates the record types it returns. This clearly distinguishes it from sibling tools like lookup_whois or check_ssl.
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 explicitly lists use cases: 'email setup verification, DNS troubleshooting, or server infrastructure research.' While it doesn't name alternative tools, the use cases are specific enough to guide selection.
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.