hmc_list_volume_groups

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

Annotations already mark this as readOnlyHint=true. The description goes beyond by describing the output structure (free space in MiB, physical volumes, virtual disks) and the parameter format (PartitionName or UUID). It does not mention error conditions or performance, but read-only safety is covered.

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 description is three short sentences with front-loaded purpose. The parameter explanation and output details are each separated cleanly, with no redundant or filler text.

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 simple read-only list operation with one parameter and an output schema, the description covers the tool's action, input semantics, and key output attributes. It gives enough context to select and invoke the tool correctly, though it could briefly mention that it returns an empty list if no volume groups exist.

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?

The input schema only lists the parameter name with no description (0% coverage). The description compensates by explaining that vios_name_or_uuid accepts either a PartitionName or UUID and points to hmc_vios for retrieval. This adds essential meaning beyond the schema.

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 opens with 'List Volume Groups on a VIOS,' which is a specific verb and resource. It also states what each volume group shows (free space, physical volumes, virtual disks), clarifying the tool's scope. This distinguishes it from sibling tools like hmc_create_volume_group or hmc_create_virtual_disk.

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?

The description gives a clear prerequisite: the parameter can be found via hmc_vios, which tells the agent how to obtain the required input. It implies the use case—inspecting volume group capacity and configured storage—but does not explicitly name alternative tools or when not to use it. This is sufficient context, though it lacks explicit exclusions.

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