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

No annotations are supplied, so the description bears the full burden. It only says 'Returns structured records' and gives no information about resolver used, error/failure behavior for nonexistent domains, rate limits, or whether lookups are cached or live. For a read-only network tool this is thin, though the risk profile is low.

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 short sentences with no filler, and the resource being queried is front-loaded. Nothing is redundant, though the trailing 'Returns structured records' sentence carries little information.

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 simple two-parameter read tool with no output schema, the description covers the essentials of what it does. It leaves gaps around the return shape (beyond 'structured'), failure modes, and differentiation from related checks, which would matter when several DNS-adjacent siblings are available.

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%, so both parameters are already documented, including the 'no scheme' constraint and the default-all behavior for types. The description's enumeration of record types merely restates the schema enum rather than adding syntax or format guidance.

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?

States a specific verb ('Query') and resource ('DNS records') and enumerates the supported record types, so the agent knows exactly what the tool retrieves. It stops short of distinguishing itself from siblings like check_mx or check_propagation, which overlap in subject matter.

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 is only implied: the description makes clear this is a general DNS lookup, so an agent can infer it is the broad option versus the specialized siblings. There is no explicit when-to-use/when-not guidance and no naming of alternatives such as check_mx or check_propagation.

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