This record as markdown: /tools/tjnull-ludus-fastmcp/add-users-to-group.md
What add_users_to_group does on Ludus FastMCP
AI agents use add_users_to_group 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 add_users_to_group is rated Medium
This tool creates or modifies group membership associations, which is a reversible data modification operation (Write category). Severity is medium because incorrect group assignments could grant unintended access to range resources or affect user permissions in a cyber range environment, but the action is reversible and the blast radius is limited to group membership changes rather than data deletion or financial…
From the tool's definition Tool name 'add_users_to_group' and description 'Add users to a group' indicates creation/modification of group membership data. This is a reversible write operation that modifies user-group relationships.
Attacks that exploit this kind of access
The rule that runs add_users_to_group 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 add_users_to_group, this is the rule to start with:
add_users_to_group 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 add_users_to_group call is checked against it from then on.
Questions about add_users_to_group
Add users to a group. 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 add_users_to_group: 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.
add_users_to_group 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 add_users_to_group 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 add_users_to_group. 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.
add_users_to_group 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.
More on Ludus Fast, and thousands of servers like it.
This server
Across the catalogue