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

readOnlyHint=true already declares the safety profile, so the bar is lower, and the description does add real semantics beyond annotations: what 'managed: true' means (NS, SOA, apex/www A while a service is attached) and the 'not-ours' case for externally-pointed domains. It says nothing about pagination, auth requirements, or failure modes, and no output schema field descriptions are confirmed to carry the 'managed'/'not-ours' semantics.

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?

It is one dense, comma-spliced sentence that front-loads the resource correctly, but the second half about return fields is heavy relative to the single input. No waste in length, but the structure makes the eligibility rule and the 'not-ours' condition hard to parse.

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?

Because an output schema exists, the description needn't enumerate return fields — yet that is where most of its words go, while the one required input is left entirely undocumented. An agent still lacks the link from domainId to a discovery sibling, which matters for a 1-required-param call.

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 0% and the single required parameter domainId carries no description at all. The description constrains what kind of domain qualifies but never says what domainId is, its format, or where to obtain it (a sibling like search_domain or list_services presumably supplies 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?

It names the exact resource ('The DNS records of a domain') and scopes it to domains 'whose zone we serve', which implicitly separates it from the mutating sibling dns_edit. The only weakness is that no verb appears — retrieval is inferred from the name/title rather than stated, and 'not-ours' is unexplained as to whether it is a value or an error.

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 parenthetical '(a purchased domain, or one connected by nameservers)' gives a genuine precondition for eligibility, and the 'not-ours' clause describes what happens outside it. But there is no explicit when-to-use instruction and no named alternative (e.g. dns_edit for changes), so routing relies on inference.

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