vm_update

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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the write/disruptive nature is covered structurally. The description adds real value beyond that: risk=medium and, critically, 'reversible → prior values', which tells the agent that a rollback path exists (consistent with the undo_list/undo_apply siblings). It stops short of saying whether the resize is disruptive to the running guest.

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-loaded tag, then a one-line purpose with the reversibility caveat, then a compact Args list. No sentence is redundant; each parameter line adds information the schema lacks.

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, the description must cover the rest, and it does cover inputs and reversibility. It omits operational prerequisites that matter for a medium-risk resize: required VM power state, whether the guest is disrupted or rebooted, and whether reducing below current usage is rejected.

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 description coverage is 0% and the schema provides only titles, so the description carries the full burden — and it does: vm_ext_id is tied to vm_list output, num_sockets and memory_bytes are defined with units and default-to-unchanged semantics, and target is explained as a config-sourced Prism Central name with a default fallback.

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?

States a specific verb+resource+scope: 'Resize a VM's CPU sockets / memory'. This is immediately distinguishable from siblings like vm_create, vm_clone, vm_migrate, and the vm_power_* family, all of which touch VMs but do something else.

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?

Usage is implied by the write tag and the mutation semantics, and the 'omit to leave unchanged' notes give per-parameter behavior. However, it never states when to choose this over vm_create/vm_clone for capacity changes, nor any prerequisite such as required power state or permissions.

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