vna_connect · Copper Mountain Vna MCP: Risk & Policy

WHAT IT DOES

What vna_connect does on Copper Mountain Vna

AI agents use vna_connect to create or update resources in Copper Mountain Vna — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Copper Mountain Vna environment.

WHY IT NEEDS A POLICY

Why vna_connect needs a policy

Establishing a TCP/IP connection to a physical instrument (VNA) creates a new network session/resource binding. It is not purely read-only (it opens a persistent connection and sets up state on both sides), not destructive, and not financial. 'Write' best captures the side-effectful nature of initiating an external connection that enables subsequent control of lab hardware.

From the tool's definition Connect to VNA at specified host:port

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vna_connect Rate-limited

vna_connect 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "vna_connect": {
      "limits": [
        {
          "counter": "vna_connect_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Copper Mountain Vna, so you can run agents against it safely.

FAQ

Questions about vna_connect

What does the vna_connect tool do? +

Connect to VNA at specified host:port. It is categorised as a Write tool in the Copper Mountain Vna MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on vna_connect? +

Register the Copper Mountain Vna MCP server in PolicyLayer and add a rule for vna_connect: 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 Copper Mountain Vna. Nothing to install.

What risk level is vna_connect? +

vna_connect is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit vna_connect? +

Yes. Add a rate_limit block to the vna_connect 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 vna_connect completely? +

Set action: deny in the PolicyLayer policy for vna_connect. 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 vna_connect? +

vna_connect is provided by the Copper Mountain Vna MCP server (rfingadam/copper-mountain-vna-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.