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

Annotations already declare readOnlyHint, idempotentHint, and closed-world scope, so the safety profile is covered. The description still adds real value: it states the single-record return, the error path when nothing matches, the zone serial/fetch semantics, and a required attribution obligation, which goes well beyond the annotations.

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 return behavior and error semantics are front-loaded before the field enumeration, and each field listed conveys distinct information. The long run-on field list is dense but every entry earns its place given the absence of an output schema.

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, the description fully carries the return-value burden via an explicit field list with types and meanings, plus error behavior and licensing/attribution requirements. An agent has everything needed to call and interpret results.

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% and the single 'name' parameter is documented as 'Domain name, e.g. example.se'. The description adds no additional syntax or formatting detail for the input itself, so the baseline of 3 is appropriate.

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 makes clear this retrieves a single domain record from the latest DNS zone snapshot, with a stated single-record return and error-on-no-match behavior. It does not distinguish itself from siblings like search_catalogue or the domains_* tools, so it stops short of a 5.

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?

There is no explicit when-to-use guidance, no exclusions, and no mention of alternative tools for finding domains (e.g., search_catalogue). The only routing hint is the error-when-no-match behavior, which is a correctness note rather than usage guidance.

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