esxi_host_summary

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so safety is covered. The description adds useful interpretive context that quickstats_* values are physical usage while VM configured memory is reported separately, which is behavioral nuance not derivable from annotations.

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?

Two short sentences with no filler, and the core purpose leads. The second sentence leans toward explaining return semantics, which partly duplicates the output schema, so it is not maximally economical.

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?

An output schema exists, so return field documentation is not required in the description. However, for a summary tool surrounded by many overlapping host/inventory siblings, the absence of any routing guidance leaves a genuine gap.

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 tool takes no parameters, so there is nothing for the description to disambiguate. The baseline for a zero-parameter tool applies, and no schema documentation debt exists.

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 resource and scope: a host capacity summary. That is a clear verb-less but concrete noun phrase distinct from esxi_health or esxi_inventory. It does not, however, explicitly contrast itself with those overlapping siblings.

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?

There is no when-to-use or when-not-to-use guidance and no named alternative, even though siblings such as esxi_health, esxi_inventory, and esxi_host_manage could plausibly be confused with a host summary. The caution about mixing metrics is interpretive, not usage guidance.

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