This record as markdown: /tools/tjnull-ludus-fastmcp/stop-testing.md
What stop_testing does on Ludus FastMCP
AI agents invoke stop_testing to trigger actions in Ludus FastMCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why stop_testing is rated High
This tool executes a state-transition command on a cyber range environment. While not destructive (testing can be resumed), it triggers external operations with effects that depend on which range is targeted. Stopping a range mid-test could interrupt security research, affect other users, or cause loss of in-progress data.
From the tool's definition Tool performs action 'stop_testing' on a range environment with command verb 'stop', which triggers state change in an active cyber range system. Description indicates it modifies operational state of testing infrastructure.
Attacks that exploit this kind of access
The rule that runs stop_testing 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 stop_testing, this is the rule to start with:
stop_testing stays usable, but rate-capped: a runaway agent can't fire it dozens of times 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 stop_testing call is checked against it from then on.
Questions about stop_testing
Stop testing state for the range. It is categorised as a Execute tool in the Ludus FastMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Ludus Fast MCP server in PolicyLayer and add a rule for stop_testing: 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.
stop_testing is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the stop_testing 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 stop_testing. 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.
stop_testing 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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