AI agents call haproxy_backend_list to retrieve information from OPNSense MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about HAProxy backends without modifying, executing, or deleting any data. It is a pure read operation that returns configuration or status information. Blast radius is minimal as listing backends cannot cause harm even if misused by an agent.
From the tool's definition Tool name 'haproxy_backend_list' and description 'List all HAProxy backends' indicate a query/retrieval operation with no side effects.
Documented attack patterns abuse exactly the kind of access haproxy_backend_list gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OPNSense MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for haproxy_backend_list:
{
"version": "1",
"default": "deny",
"tools": {
"haproxy_backend_list": {}
}
}haproxy_backend_list is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all HAProxy backends. It is categorised as a Read tool in the OPNSense MCP Server MCP Server, which means it retrieves data without modifying state.
Register the OPNSense MCP Server MCP server in PolicyLayer and add a rule for haproxy_backend_list: 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 OPNSense MCP Server. Nothing to install.
haproxy_backend_list 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 haproxy_backend_list 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 haproxy_backend_list. 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.
haproxy_backend_list is provided by the OPNSense MCP Server MCP server (vespo92/opnsensemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 196 OPNSense MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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196 OPNSense MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.