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

Annotations already declare readOnly, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely useful behavioral detail about what is queried (DS, DNSKEY, AD flag), but says nothing about behavior when DNSSEC is absent/unsigned or about query failures, which is the case an agent most needs framed.

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?

A single front-loaded sentence that names what is checked and what verdict is derived, with no filler.

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?

With no output schema, a single obvious parameter, and annotations covering the safety profile, the description gives enough to call the tool correctly and interpret its purpose. A note on unsigned-domain results would make it complete.

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?

One required parameter with 0% schema description coverage; the description only implies the parameter via 'for a domain'. The domain argument is self-evident in form, so the gap is minor, but no format guidance (apex name vs. hostname, IDN, trailing dot) is provided.

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?

Names the specific records (DS, DNSKEY) and the exact signal evaluated (AD flag from a validating resolver), so the agent knows this is a DNSSEC validation check rather than a generic DNS lookup. It is distinguishable from siblings like check_dns_propagation or check_domain_delegation by the resources named, though no sibling is named explicitly.

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 implied by the resource: use it when you need to know whether a domain is DNSSEC-signed and validating. There is no explicit when-to-use/when-not, and no pointer to alternatives such as check_domain_delegation for delegation-only questions.

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