This record as markdown: /tools/tjnull-ludus-fastmcp/assign-range-to-user.md
What assign_range_to_user does on Ludus FastMCP
AI agents use assign_range_to_user 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.
Why assign_range_to_user is rated Medium
The tool modifies user-to-range mappings in what appears to be a cyber range management system. This is a Write operation because it creates or updates access records without irreversible deletion. Severity is medium because assignment mistakes could grant unintended access to sensitive testing environments, but the action is reversible (permissions can be reassigned or revoked).
From the tool's definition Tool description states 'Assign range access to a user' — this creates or modifies access control assignments, changing permissions reversibly.
Attacks that exploit this kind of access
The rule that runs assign_range_to_user safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Ludus FastMCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For assign_range_to_user, this is the rule to start with:
assign_range_to_user 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Ludus FastMCP, apply this rule, and every assign_range_to_user call is checked against it from then on.
Questions about assign_range_to_user
Assign range access to a user. 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 assign_range_to_user: 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.
assign_range_to_user 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 assign_range_to_user 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 assign_range_to_user. 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.
assign_range_to_user 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.
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