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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds meaningful behavioral context beyond that: the catalog is synced daily, exposes when it last changed, and carries a conservative default install version. It does not discuss return format or any failure modes, but for a read-only catalog that omission is minor.

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?

Front-loaded with the core purpose and return content before the imperative usage directive. The first sentence is dense and long, packing many returned fields together, but no clause is filler and the routing advice is placed last where it reads naturally.

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 carries the full burden of explaining what comes back, and it does so in detail (latest version, stable_version logic, supported minor channels, patch versions with dates, last-changed timestamp). Combined with the strong usage directive, an agent has everything needed to call it correctly.

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 coverage is 100% and the single 'engine' parameter is fully documented in the schema, including the enum values and their meanings. The description restates the same kubeadm/k3s distinction and 'omit for both' behavior, so it reinforces rather than extends the schema. Baseline 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?

States a specific verb and resource ('List the Kubernetes versions') plus the source of truth (upstream version catalog synced daily from kubernetes/kubernetes and k3s feeds). It distinguishes the two engines it covers and enumerates the returned fields, so an agent can differentiate it from siblings like list_managed_k8s_options or roll_cluster_to_version.

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?

Explicit when-to-use: 'ALWAYS call this before answering any question about the latest, current, or supported Kubernetes/k3s versions, and before picking a version for cluster create or upgrade.' Also gives the exclusion ('never answer version questions from training memory') and the alternative for uncovered data ('follow up with web_fetch on kubernetes.io/releases').

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