List users with access to a range. Args: range_id: Range ID to list users for Returns: List of users with access to the range
AI agents call list_range_users 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.
This tool retrieves and enumerates user access information for a specified range. It performs no creation, modification, deletion, code execution, or financial operations. The action is purely informational—listing existing users—which is the hallmark of a Read category tool.
From the tool's definition Tool name 'list_range_users' and description 'List users with access to a range' indicates a query/retrieval operation that returns information without modifying state.
Documented attack patterns abuse exactly the kind of access list_range_users 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_range_users:
{
"version": "1",
"default": "deny",
"tools": {
"list_range_users": {}
}
}list_range_users is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List users with access to a range. Args: range_id: Range ID to list users for Returns: List of users with access to the range. It is categorised as a Read tool in the Ludus FastMCP MCP Server, which means it retrieves data without modifying state.
Register the Ludus Fast MCP server in PolicyLayer and add a rule for list_range_users: 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.
list_range_users is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_range_users 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 list_range_users. 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.
list_range_users 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.
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201 Ludus FastMCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.