vm_performance

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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, destructiveHint false. The description adds behavioral details: powered-off VMs are skipped, point-in-time only, and that limit=None returns all VMs. No contradiction with 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?

The description is well-structured with a summary line followed by details and parameter descriptions. It front-loads the purpose and uses clear language. Slightly verbose with the Args section, but still 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?

Given the complexity and existence of an output schema, the description covers key aspects: returned fields, ordering, scope (powered-on, busiest first), and limit behavior. It does not detail error cases or output format, but output schema handles that.

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?

Schema coverage is 0%, so the description must compensate. It explains vm_name for filtering single VM, target as optional vCenter, and limit with default and usage of None. This adds meaningful semantics 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 clearly states the tool reads real-time CPU/memory/disk/network utilization per virtual machine, specifying the resource (VM), verb (READ), and scope (powered-on only, busiest first). It distinguishes from trend tools and siblings like host_performance by focusing on VM-level metrics.

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 clear context: when to use (real-time utilization of powered-on VMs), when not (point-in-time only, use metrics store for trends), and default behavior (top 25, limit=None for all). It does not explicitly compare with siblings but the VM-specific focus implies differentiation.

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