datastore_capacity

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

Annotations already convey readOnly and idempotent behavior. The description adds behavioral context beyond that: the list is ordered 'riskiest first', it is 'point-in-time', and it explains the overcommit semantics (over 100% means more promised than physically exists, thin datastore can fill while showing free). This goes beyond the annotation baseline, enriching agent understanding.

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?

Every sentence earns its place: first sentence states the core purpose and return fields, second explains the unique risk signal, third provides usage and drilldown guidance. There is no filler, and the core information is front-loaded. The structure is tight and efficient.

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-based list tool with no output schema, the description fully specifies the return fields, ordering, point-in-time nature, and the key risk concept. It also covers the follow-up actions and ownership boundaries. An agent has everything needed to decide when and how to invoke it correctly.

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 description coverage is 100% (both 'limit' and 'target' are documented in the schema). The description does not add any parameter-specific meaning beyond what the schema already provides, so the baseline of 3 is appropriate. No additional value is needed.

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 '(READ) Per-datastore capacity with thin-provisioning over-commit.' It specifies the resource (datastores) and the unique angle (thin-provisioning over-commit, risk signal) and explicitly contrasts with list_all_datastores, which it says lacks the overcommit signal. This distinguishes it from siblings without ambiguity.

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 states when to use it (capacity view) and then routes to datastore_investigation_bundle for drilling into hosts/VMs/alarms, and to vmware-aiops for reclaiming actions. This provides explicit context and alternatives, fulfilling the usage guidance requirement fully.

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