dns_lookup

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

With no annotations provided, the description carries the burden of behavioral disclosure. It adds the specific behavioral detail that queries go over DNS-over-HTTPS, and the list of supported record types clarifies the scope. However, it does not mention potential edge cases like NXDOMAIN responses or rate limits, though these are minor for a read-only DNS lookup.

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 that immediately states the action and scope. Every word adds value, including the parenthetical note about the transport method.

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 single-parameter tool with an output schema, the description is adequately comprehensive. It specifies the exact record types supported and the resolution method. The simple nature of the DNS lookup means no additional context about pagination or error handling is strictly necessary, though mentioning the absence of other record types could have added clarity.

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 only defines 'domain' as a required string with no description. The description adds meaning by stating the tool resolves records 'for a domain,' confirming the parameter is a domain name. However, it does not clarify expected formats (e.g., no protocol, no trailing dot) or examples, so the description only partially compensates for the 0% schema coverage.

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 uses the specific verb 'Resolve' and lists concrete record types (A/AAAA/MX/NS/TXT/CNAME), clearly distinguishing this DNS lookup tool from sibling tools like recon_subdomains and whois. The 'via DNS-over-HTTPS' detail further specifies the method, leaving no ambiguity about what the tool does.

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 clearly implies the tool is for DNS record lookup requests, and the explicit list of record types sets expectations. However, it does not explicitly state when to prefer this over alternatives or when not to use it, though no sibling tool overlaps with DNS record resolution directly.

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