AI agents call health_check to retrieve information from N Lobby MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
A health check is a read-only operation that tests API availability and responsiveness. It performs no data retrieval, modification, execution, destruction, or financial action. The blast radius of misuse is minimal—an attacker could only determine whether the service is online or offline, which is typically not sensitive information. This is a standard diagnostic tool with no side effects.
From the tool's definition Tool name 'health_check' and description 'Check if N Lobby API connection is working' indicate a diagnostic query that verifies service connectivity status without retrieving or modifying any data.
Documented attack patterns abuse exactly the kind of access health_check gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and N Lobby MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for health_check:
{
"version": "1",
"default": "deny",
"tools": {
"health_check": {}
}
}health_check is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Check if N Lobby API connection is working. It is categorised as a Read tool in the N Lobby MCP Server MCP Server, which means it retrieves data without modifying state.
Register the N Lobby MCP Server MCP server in PolicyLayer and add a rule for health_check: 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 N Lobby MCP Server. Nothing to install.
health_check 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 health_check 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 health_check. 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.
health_check is provided by the N Lobby MCP Server MCP server (minagishl/nlobby-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from N Lobby MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
28 N Lobby MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.