Modify a stopped managed QEMU VM definition to change CPU, memory, accelerator, profile, or other settings before restarting it.
Update a stopped managed QEMU VM definition, including accelerator policy and any profile component.
| Name | Required | Description | Default |
|---|---|---|---|
| cpus | No | ||
| name | No | ||
| vm_id | Yes | ||
| memory | No | ||
| machine | No | ||
| profile | No | ||
| overrides | No | ||
| extra_args | No | ||
| qemu_binary | No | ||
| acceleration | No | ||
| architecture | No | ||
| profile_overrides | No |
Changes observed during successful MCP inspections.
v1.6.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and readOnlyHint=false, and the description does not contradict them. The description adds useful context by noting the VM must be stopped and that the update covers accelerator policy and profile components. However, it does not disclose merge/replace behavior, side effects, or whether the update is applied immediately or requires a subsequent action.
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 a single, front-loaded sentence with no filler. It states the action, the precondition, and the scope efficiently, making it easy for an agent to parse quickly.
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 destructive, non-idempotent mutation tool with 12 parameters, nested objects, no output schema, and zero schema-described parameters, the one-sentence description is insufficient. It provides the stopped-VM precondition but omits parameter semantics, return behavior, and operational details needed for reliable use.
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%, so the description needed to compensate, but it only hints at 'accelerator policy' and 'profile component'. It does not explain the meaning or usage of the 12 parameters such as cpus, memory, overrides, extra_args, qemu_binary, or architecture. This is a significant gap for an agent trying to invoke the tool correctly.
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 uses the specific verb 'Update' with a clear resource: 'a stopped managed QEMU VM definition'. It distinguishes this from sibling tools like qemu_vm_create, qemu_vm_start, and qemu_vm_delete by focusing on modifying an existing stopped definition. The phrase 'including accelerator policy and any profile component' further clarifies the scope.
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 explicitly states the key precondition 'stopped', which tells the agent when this tool is applicable versus other qemu_vm_* operations. It does not explicitly name alternative tools or say 'use qemu_vm_create for new VMs', but the context is clear enough for appropriate selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.