Low Risk

list_hosts

List all hosts in range. Args: user_id: Optional user ID (admin only) Returns: List of hosts

How to control list_hosts ↓

AI agents call list_hosts to retrieve information from Ludus FastMCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

This tool retrieves or queries information about hosts in a cyber range environment without modifying, executing, or deleting anything. It is a straightforward read operation that returns data. The admin-only parameter for user_id suggests access restrictions but does not elevate the risk category. Even in a cyber range context, listing hosts poses minimal risk as it only exposes inventory information.

From the tool's definition Tool name is 'list_hosts' and description states it 'List all hosts in range' with a return value of 'List of hosts'.

Risk signalsAdmin/system-level operation

Documented attack patterns abuse exactly the kind of access list_hosts 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 list_hosts:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_hosts": {}
  }
}

list_hosts is read-only, so it stays allowed — but 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.
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Go deeper

What does the list_hosts tool do? +

List all hosts in range. Args: user_id: Optional user ID (admin only) Returns: List of hosts. It is categorised as a Read tool in the Ludus FastMCP MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_hosts? +

Register the Ludus Fast MCP server in PolicyLayer and add a rule for list_hosts: 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 list_hosts? +

list_hosts is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_hosts? +

Yes. Add a rate_limit block to the list_hosts 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 list_hosts completely? +

Set action: deny in the PolicyLayer policy for list_hosts. 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 list_hosts? +

list_hosts 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.

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