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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, so the safety profile is covered. Description adds that results include TTL and raw data, providing marginal behavioral context (output richness) but does not disclose potential rate limits, caching, or service dependencies beyond the reference to WhoisXML.

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?

Single sentence that is information-dense and front-loaded. Every word contributes to clarity without redundancy.

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?

Given the presence of an output schema, the description need not explain return structure. The tool is simple (2 parameters, one required). The description adequately covers the operation and record types, though it could mention that it queries a third-party service (WhoisXML) with potential implications.

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%, with both 'domain' and 'record_type' described in the schema. The description lists record types already present in the enum, adding no new semantic information beyond what the schema provides.

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?

Description explicitly states 'Get DNS records for a domain' and enumerates specific record types (A, AAAA, MX, etc.), clearly differentiating from sibling WHOIS and DNS tools by emphasizing DNS record retrieval with TTL and raw data from WhoisXML.

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 context is implied through the description (DNS lookup), but no explicit guidance on when to use this tool versus alternatives like whois.domain.lookup or whoisjson.dns.subdomains. No exclusions or prerequisites mentioned.

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