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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, so the safety profile is covered. Since there is no output schema, the description adds real value by enumerating the exact fields the response exposes (type primary/alias, www, redirection, wildcard, DNS integration, status). It does not mention auth or pagination behavior, but pagination is handled in the schema.

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 compact sentences: the field list first, then the endpoint. Nothing is padded, and the return fields are front-loaded. It is terse to the point that the actual 'list' verb is missing, which is a minor structural weakness.

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 read-only list tool with full schema coverage and read-only/non-destructive annotations, the definition supplies what the structured fields don't: the returned field set and the resource path. No output schema exists, yet the description compensates by naming the response fields. Missing only explicit usage routing against siblings.

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 server_id/webapp_id and the page/per_page parameters are already documented in the schema. The description contributes only the path template '/servers/{id}/webapps/{webapp}/domains', which loosely signals the two required path params but adds no new semantics. Baseline 3 applies.

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 names the specific resource (domain names of a web application) and enumerates the fields returned (id, name, type, www, redirection, etc.), plus the exact endpoint GET /servers/{id}/webapps/{webapp}/domains. This makes the operation identifiable without opening the schema. It stops short of 5 because the verb 'list/get' is only implied by the endpoint, and no sibling (e.g. runcloud_get_domain_dns) is named to disambiguate.

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 guidance on when to call this versus the similarly-named sibling runcloud_get_domain_dns, and no prerequisites or exclusions are stated. The reader must infer usage entirely from the noun phrase and endpoint path.

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