get_vcenter_deployment_size

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

Annotations already declare readOnlyHint/idempotentHint, and the description goes well beyond them: it explains the response envelope {available, note, fields}, that available:False signals a 503 or pre-9.1 vCenter with reason distinguishing them, and that this is not a failure condition. This is exactly the failure-mode disclosure an agent needs and cannot get from structured fields.

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?

Front-loads the [READ] marker and purpose, then uses short labeled blocks (When to use, What it returns, Gotchas) so an agent can scan the relevant part. Slightly redundant between the "What it returns" and "Gotchas" mentions of the 9.1/available:False behavior, keeping it short of a 5.

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 present, the description fully covers the return envelope and its non-obvious sentinel value, plus the version prerequisite that gates the endpoint. Nothing an agent needs to interpret a result or diagnose an empty response is missing.

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?

Only one optional parameter (target) with 100% schema description coverage, so the schema already carries its meaning. The description adds no syntax, defaulting, or target-selection detail beyond the schema, which is the expected baseline when the schema is complete.

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?

Names a specific verb and resource (read vCenter appliance deployment size) and immediately scopes it against the rest of the toolset by noting it covers capacity-planning context that inventory/perf tools do not. An agent can tell it apart from list_all_* and get_*_performance siblings without opening the schema.

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?

Includes an explicit "When to use" block and states what this tool covers that inventory/perf tools do not, giving both the selecting condition and the boundary against adjacent categories. No ambiguity about when to reach for it.

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