vsphere_list_datastores

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context by explaining the over-provisioning semantics ('provisioned_gib includes space promised to thin disks that has not been written yet, so it can exceed capacity_gib') and what 'overprovisioned' flags. This goes beyond the annotations without contradicting them.

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 efficiently structured: a crisp lead sentence defining the primary purpose, a one-sentence explanation of a nuanced output concept, and a tightly organized Args list. Every line adds information without redundancy or 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 read-only list tool with both input schema and output schema present, the description covers the tool's output semantics (capacity, free space, provisioned_gib, overprovisioned) and all parameters, including their purpose and allowed patterns. It provides sufficient context for an agent to decide when and how to invoke it, especially given the strong annotations.

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 schema has 0% description coverage, so the description carries full parameter documentation. The 'Args:' section adds meaningful detail for each parameter: name supports 'substring, or glob with * / ?', datastore_type gives example values like 'VMFS', 'NFS' or 'vsan', and min_used_percent explicitly states its use case. This fully compensates for the missing schema descriptions.

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 a clear, specific verb+resource statement: 'List datastores with capacity, free space and over-provisioning.' This unambiguously identifies the tool's purpose and distinguishes it from sibling list tools by the resource type and the specific metrics covered.

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 provides strong contextual guidance, such as 'min_used_percent: Only datastores at or above this utilisation, for spotting the ones about to fill up,' explaining why you'd use this filter. However, it does not explicitly compare against alternatives like vsphere_search_inventory or other list tools, so it stops short of giving explicit when/when-not guidance.

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