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

Annotations declare readOnlyHint=true, and the description confirms read-only while adding substantial context beyond them: platform allocation of hostnames, the meaning of public_hostnames_available=false, and the three dns_publication states including the caveat that publisher_present is only an install check and a wedged publisher can still read present. Minor deduction because this is largely return-value semantics rather than call-time behavior, but the operational warnings are genuinely useful.

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 purpose is front-loaded, but the body is a single enormous run-on sentence dense with em-dashes and nested parentheticals, which is hard to parse. Given there is no output schema some return-field detail is justified, but the wording could be materially tightened without losing meaning.

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 compensates by naming and explaining every returned concept: root domain, delegated zone, cluster subzone and state, demo_base_domain override, cluster_domain and its source, public_hostname_suffix, public_hostnames_available, and dns_publication. Nothing an agent needs to interpret the result is missing.

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 there is only one optional parameter (cluster_id), so the schema already documents it fully. The description only indirectly references cluster selection via 'the selected cluster's delegated subzone'. Baseline 3 is appropriate when the schema carries the parameter burden.

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 (get) and resource (preview domain / DNS zones and public hostname suffix) and enumerates exactly which fields it returns. It is clearly distinguishable from siblings like get_cluster_dns_zone and list_cluster_custom_dns_zones because it describes the publishing-capable suffix rather than raw zone inventory.

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?

Gives an explicit, unambiguous directive: 'ALWAYS call this before proposing, promising, or configuring any public hostname, Ingress host, demo URL, or preview URL'. It also explains the constraint that hostnames are platform-allocated, which tells the agent why the tool must precede those actions.

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