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

readOnlyHint=true already establishes the safe read profile, and the description adds genuine value beyond that by disclosing what a size record contains (CPU cores, RAM, disk, transfer allowance, GPU) — useful since no output schema exists. It stops short of pagination or ordering behavior, keeping it out of the top band.

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?

One sentence plus the underlying API route; the scope of coverage and returned fields are front-loaded with no filler. Every clause carries information.

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 zero-required-param read-only list tool with fully documented schema and no output schema, the description covers purpose, scope and return attributes adequately. Pagination/response-shape details are the only meaningful omission.

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 region parameter is already richly documented in the schema (format, examples, CIVO_REGION fallback, regionality). The description adds nothing about region, so the 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?

States a specific verb (List) plus resource (sizes/plans) and immediately scopes what it covers — instances, Kubernetes nodes and databases — and enumerates the returned attributes. No sibling tool does this, so an agent can place it unambiguously in the catalog.

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?

Usage is only implied: a read-only list of launchable plans is naturally consulted before provisioning, but the description never says when to call it or that it precedes instance/database/cluster creation. No alternatives are named, so an agent must infer placement from context alone.

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