AI agents call list_vlans 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 performs a read-only operation to enumerate VLANs on the OPNsense firewall. It has no side effects, creates no modifications, and poses minimal risk if misused by an AI agent — the worst outcome would be information disclosure about network topology. This clearly falls under the 'Read' category for data retrieval operations.
From the tool's definition Tool name is 'list_vlans' and description states 'List all VLANs' — a query operation that retrieves VLAN configuration data without modifying any state.
Documented attack patterns abuse exactly the kind of access list_vlans 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 list_vlans:
{
"version": "1",
"default": "deny",
"tools": {
"list_vlans": {}
}
}list_vlans 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 VLANs. 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 list_vlans: 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.
list_vlans 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 list_vlans 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 list_vlans. 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.
list_vlans 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.