Medium Risk

apply_template

Apply a template to a VM. Args: vm_name: Name of the VM to apply template to template_id: Template ID to apply user_id: Optional user ID (admin only) Returns: Template application result

How to control apply_template ↓

AI agents use apply_template to create or update resources in Ludus FastMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ludus FastMCP environment.

Medium Risk

Applying a template to a VM modifies the VM's configuration or state. This is a Write operation as it changes an existing resource. The severity is high because misconfiguring a VM in a cyber range environment could disrupt running security tests or scenarios, and the operation may be difficult to reverse without knowing the prior state.

From the tool's definition Apply a template to a VM

Risk signalsAdmin/system-level operation

Documented attack patterns abuse exactly the kind of access apply_template gives an agent:

PolicyLayer is an MCP gateway — it sits between your AI agents and Ludus FastMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for apply_template:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "apply_template": {
      "limits": [
        {
          "counter": "apply_template_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

apply_template 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.

  1. Create a free account and register Ludus FastMCP — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

Free to start. No card required.

Go deeper

What does the apply_template tool do? +

Apply a template to a VM. Args: vm_name: Name of the VM to apply template to template_id: Template ID to apply user_id: Optional user ID (admin only) Returns: Template application result. It is categorised as a Write tool in the Ludus FastMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on apply_template? +

Register the Ludus Fast MCP server in PolicyLayer and add a rule for apply_template: 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 Ludus FastMCP. Nothing to install.

What risk level is apply_template? +

apply_template is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit apply_template? +

Yes. Add a rate_limit block to the apply_template 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.

How do I block apply_template completely? +

Set action: deny in the PolicyLayer policy for apply_template. 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.

What MCP server provides apply_template? +

apply_template is provided by the Ludus Fast MCP server (tjnull/ludus-fastmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Ludus FastMCP tool call.

Deterministic rules across all 201 Ludus FastMCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

201 Ludus FastMCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

// GET IN TOUCH

Have a question or want to learn more? Send us a message.

Message sent.

We'll get back to you soon.