opn_list_acme_certs

THE RISK

Low Risk

Why opn_list_acme_certs needs a policy

List operations are Read category—they retrieve information about existing resources without modifying or deleting anything. While the tool description is empty, the name strongly indicates a read-only query of ACME certificate inventory. Confidence is moderately high based on the 'list' verb pattern, but slightly reduced due to lack of descriptive text.

From the tool's definition Tool name 'opn_list_acme_certs' uses the verb 'list', which retrieves/queries data without side effects. The 'acme_certs' refers to ACME (Automatic Certificate Management Environment) certificates managed by OPNsense.

Documented attack patterns abuse exactly the kind of access opn_list_acme_certs gives an agent:

POLICY

How to control opn_list_acme_certs

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_list_acme_certs:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "opn_list_acme_certs": {}
  }
}

opn_list_acme_certs is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register OPNsense MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More OPNsense MCP Server tools

Destructive opn_delete_alias opn_delete_alias Destructive opn_delete_ddns_account Delete a Dynamic DNS account by UUID and apply the configuration. Destructive opn_delete_dns_override opn_delete_dns_override Destructive opn_delete_dnsmasq_range Delete a dnsmasq DHCP range by UUID and apply the configuration. Destructive opn_delete_firewall_category opn_delete_firewall_category Destructive opn_delete_firewall_rule opn_delete_firewall_rule Destructive opn_delete_nat_rule opn_delete_nat_rule Destructive opn_haproxy_delete opn_haproxy_delete

All 81 OPNsense MCP Server tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about opn_list_acme_certs

What does the opn_list_acme_certs tool do? +

opn_list_acme_certs. It is categorised as a Read tool in the OPNsense MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on opn_list_acme_certs? +

Register the OPNsense MCP Server MCP server in PolicyLayer and add a rule for opn_list_acme_certs: 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.

What risk level is opn_list_acme_certs? +

opn_list_acme_certs is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit opn_list_acme_certs? +

Yes. Add a rate_limit block to the opn_list_acme_certs 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.

How do I block opn_list_acme_certs completely? +

Set action: deny in the PolicyLayer policy for opn_list_acme_certs. 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.

What MCP server provides opn_list_acme_certs? +

opn_list_acme_certs 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.

Enforce policy on every OPNsense MCP Server tool call.

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.

CHECK YOUR STACK →