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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the risk profile is covered. The description does add real value beyond them: the cost/scope note ('provisions no infrastructure and costs nothing on its own'), the deliberate 403 ambiguity between missing and inaccessible clusters, and the fact that only non_essential is updatable. However it never says what 'update' destroys or how the non_essential toggle affects existing metrics, so it does not fully exploit the room annotations leave open.

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?

Five short paragraphs, each carrying distinct load: identity/scope, cost and isolation model, the 403 trap, update limits, default semantics, and the preview workflow. Purpose is front-loaded in the first clause, and nothing is padding.

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 destructive, non-idempotent mutation with 6 parameters and no output schema, the description covers scope, cost, error semantics, the updateable field, the no-action default, and the mandatory preview/confirm cycle. There is no return-value explanation needed and none 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%, so the baseline is 3. The description goes beyond the schema by framing the omit-action default in practical terms ('just ensures the cluster exists... reports an existing one unchanged') and by connecting the 403 quirk to why a bare create can fail, which is the semantic an agent is most likely to get wrong when choosing action values.

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 states a specific verb+resource pair ('create or update a cluster') and immediately defines what a cluster is ('Cycle's unit of physical isolation, grouping servers that share a private network'). It distinguishes itself from siblings by routing the agent to list_servers for inspection and deploy_servers for adding servers, so the agent can place this tool without opening a schema.

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?

It gives explicit when-to-use context (separate clusters for dev/staging/prod), names the sibling tools to use instead for other steps (list_servers, deploy_servers), and rules things out ('Cycle exposes no rename, and monitoring tiers are configured elsewhere'). The mandatory preview-then-confirm workflow is stated as a hard rule, leaving no inference.

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