vna_set_port_extension · Copper Mountain Vna MCP

WHAT IT DOES

What vna_set_port_extension does on Copper Mountain Vna

AI agents use vna_set_port_extension 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_set_port_extension needs a policy

This tool modifies analyzer state by setting calibration/compensation parameters for measurement ports. Changes are reversible (can be re-set or cleared via vna_clear_port_extension), making it Write rather than Destructive. However, it affects measurement accuracy and could lead to incorrect test results or invalid calibration if misconfigured, justifying medium severity.

From the tool's definition Tool name contains 'set' and description states it modifies port extension parameters (delay and/or loss compensation). This is a configuration change to the network analyzer's measurement setup.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vna_set_port_extension Rate-limited

vna_set_port_extension 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_set_port_extension": {
      "limits": [
        {
          "counter": "vna_set_port_extension_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_set_port_extension

What does the vna_set_port_extension tool do? +

Set port extension to compensate for cables/fixtures (delay and/or loss). 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_set_port_extension? +

Register the Copper Mountain Vna MCP server in PolicyLayer and add a rule for vna_set_port_extension: 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_set_port_extension? +

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

Can I rate-limit vna_set_port_extension? +

Yes. Add a rate_limit block to the vna_set_port_extension 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_set_port_extension completely? +

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

vna_set_port_extension 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.