AI agents use opn_haproxy_add to create or update resources in OPNsense MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your OPNsense MCP Server environment.
The 'add' verb and HAProxy context suggest this tool creates or modifies HAProxy configuration objects, which is a reversible data modification operation (Write category). HAProxy manages critical load balancing and routing, so misuse could redirect traffic or create network access paths (high severity).
From the tool's definition Tool name 'opn_haproxy_add' indicates addition/creation of HAProxy configuration; description is empty but naming convention aligns with sibling tools like 'opn_add_firewall_rule', 'opn_add_nat_rule' which are Write operations.
Documented attack patterns abuse exactly the kind of access opn_haproxy_add 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 opn_haproxy_add:
{
"version": "1",
"default": "deny",
"tools": {
"opn_haproxy_add": {
"limits": [
{
"counter": "opn_haproxy_add_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}opn_haproxy_add 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.
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opn_haproxy_add. It is categorised as a Write tool in the OPNsense MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the OPNsense MCP Server MCP server in PolicyLayer and add a rule for opn_haproxy_add: 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.
opn_haproxy_add 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 opn_haproxy_add 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 opn_haproxy_add. 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.
opn_haproxy_add is provided by the OPNsense MCP Server MCP server (lucamarien/opnsense-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from OPNsense MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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81 OPNsense MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.