DNS lookup

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

The annotations already declare read-only and non-destructive behavior, but the description adds valuable behavioral details beyond that: it returns TTLs and reports NXDOMAIN as an empty result rather than an error. This enriches the agent's understanding of the tool's runtime behavior.

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 exceptionally concise — two short sentences — yet conveys all essential information: the action, target, method, and key behavioral notes. There is no redundancy or extraneous detail.

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 tool's simple nature, the description is complete. It covers what the tool does, how it behaves on success and failure (NXDOMAIN), and what the return contains (TTLs). No additional context is needed for an agent to call it correctly.

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 is fully covered with descriptions for both parameters (domain and record_type), including an enum for record_type and a default. The description does not add significant semantic information beyond what the schema already provides, so it meets the baseline but does not exceed it.

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 specific action — resolving a DNS record — and the resource (a domain) via DNS-over-HTTPS. It also clarifies the return format (records with TTLs) and edge-case behavior (NXDOMAIN as empty result), 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 gives a clear context for when to use the tool (for DNS record resolution) but does not explicitly compare it to the sibling tools (tls_certificate, http_probe, ip_rdap) or state when not to use it. The context is sufficient to infer appropriate usage, though explicit exclusions would make it stronger.

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