AI agents use create_custom_os_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.
This tool creates a new OS template, which is a reversible data structure within the Ludus cyber range system. While template creation itself is Write-level, the high severity reflects that custom OS templates in a cyber range could be maliciously designed to compromise test environments or introduce vulnerabilities.
From the tool's definition Tool name 'create_custom_os_template' indicates creation of a new template artifact. Server context shows management of 'cyber range environments' and 'template creation' capabilities. The prefix 'create_' is a strong Write signal.
Documented attack patterns abuse exactly the kind of access create_custom_os_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 create_custom_os_template:
{
"version": "1",
"default": "deny",
"tools": {
"create_custom_os_template": {
"limits": [
{
"counter": "create_custom_os_template_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_custom_os_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.
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create_custom_os_template. 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.
Register the Ludus Fast MCP server in PolicyLayer and add a rule for create_custom_os_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.
create_custom_os_template 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 create_custom_os_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.
Set action: deny in the PolicyLayer policy for create_custom_os_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.
create_custom_os_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.
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.