Clone an existing VM, creating a copy with a new name.
AI agents use vm_clone to create or update resources in Truenas — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Truenas environment.
Cloning a VM creates a new copy of an existing virtual machine, which is a reversible write/create operation. It does not delete or overwrite existing data, nor does it execute arbitrary code. However, it can consume significant storage and compute resources, giving it a high severity if misused by an AI agent creating many clones.
From the tool's definition Clone an existing VM, creating a copy with a new name
Documented attack patterns abuse exactly the kind of access vm_clone gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Truenas, and nothing reaches the server without passing your rules. This is the rule we recommend for vm_clone:
{
"version": "1",
"default": "deny",
"tools": {
"vm_clone": {
"limits": [
{
"counter": "vm_clone_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}vm_clone stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Clone an existing VM, creating a copy with a new name. It is categorised as a Write tool in the Truenas MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Truenas MCP server in PolicyLayer and add a rule for vm_clone: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Truenas. Nothing to install.
vm_clone is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the vm_clone rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for vm_clone. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
vm_clone is provided by the Truenas MCP server (spranab/truenas-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Truenas, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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279 Truenas tools catalogued and risk-classified — across an index of 43,000+ MCP servers.