vna_define_limit · Copper Mountain Vna MCP: Risk & Policy

WHAT IT DOES

What vna_define_limit does on Copper Mountain Vna

AI agents use vna_define_limit 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_define_limit needs a policy

This tool creates or modifies limit definitions used for pass/fail evaluation of measurements. It writes configuration data to the VNA instrument. It is reversible (limits can be redefined or cleared, as evidenced by the sibling tool vna_clear_limits). No code execution, deletion, or financial impact involved.

From the tool's definition Define pass/fail limit for measurements

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vna_define_limit Rate-limited

vna_define_limit 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_define_limit": {
      "limits": [
        {
          "counter": "vna_define_limit_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_define_limit

What does the vna_define_limit tool do? +

Define pass/fail limit for measurements. 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_define_limit? +

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

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

Can I rate-limit vna_define_limit? +

Yes. Add a rate_limit block to the vna_define_limit 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_define_limit completely? +

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

vna_define_limit 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.