DNS Lookup

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

With annotations already indicating readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, the description adds context by specifying the exact record types returned and the 'one query' behavior. This provides useful behavioral details beyond the annotations, such as the comprehensive response scope.

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 two sentences, each earn its place: the first defines the action and scope, the second lists outcomes. No redundant wording, and key information is 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?

No output schema exists, so the description appropriately explains return values by listing record types. It gives the essential context for a simple read-only tool, though it could specify the response format (e.g., JSON) or edge cases, but that is beyond minimal expectations. The sibling context and annotations further round out completeness.

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 description for domain_name already covers its purpose and format, giving 100% coverage. The tool description does not elaborate further on parameters, but since the schema is explicit, the baseline of 3 is appropriate; no additional semantic clarification is needed.

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 tool's function: 'Look up all DNS records for a domain in one query.' It specifies the resource (domain), the action (look up), and the full scope of record types returned, distinguishing it from sibling tools that handle specific record types like cname_lookup or mx_lookup.

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 implies when to use the tool: when you need multiple record types at once ('all DNS records in one query'). It does not explicitly name alternatives, but the list of sibling tools and the explicit enumeration of record types make the usage context clear, though it lacks direct exclusions or alternative references.

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