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

The readOnlyHint annotation already establishes the safe-read profile, and the description adds real value on top: it discloses the returned attributes and the billing nuance that unattached volumes still incur charges. It omits pagination and rate-limit behavior, keeping it short of a 5.

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?

A single front-loaded sentence covering scope and output, plus a compact endpoint reference. Every clause carries information; nothing is filler or repeated.

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 usefully enumerates the fields returned and notes the attachment target, which is exactly what an agent needs to interpret results. Only pagination/return-order behavior is left unstated.

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%: the region parameter already carries the pattern, examples, the CIVO_REGION default, and a pointer to civo_list_regions. The description's 'in a region' only reinforces what the schema states, 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?

The description names a specific verb and resource ('List the block-storage volumes'), scopes it ('in a region'), and enumerates the returned fields (size, status, type, attachment target). No sibling tool lists volumes, so an agent can immediately place this as the only volume-inventory read.

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: it operates within a region and the schema references civo_list_regions for valid codes. There is no explicit statement of when to reach for this versus, say, civo_list_instances or civo_list_charges, and no exclusions.

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