vna_scpi_query · Copper Mountain Vna MCP: Risk & Policy

WHAT IT DOES

What vna_scpi_query does on Copper Mountain Vna

AI agents invoke vna_scpi_query to trigger actions in Copper Mountain Vna. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why vna_scpi_query needs a policy

Although named 'query', this tool executes arbitrary SCPI commands on real laboratory hardware. SCPI queries can trigger instrument state changes, sweeps, or calibration routines depending on the command sent. The ability to send arbitrary commands to physical test equipment carries high risk of misconfiguration or hardware damage, placing this firmly in Execute rather than Read.

From the tool's definition 'Send SCPI query and return response' — sends arbitrary SCPI commands to physical VNA hardware over TCP/IP

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vna_scpi_query Rate-limited

vna_scpi_query stays usable, but rate-capped — a runaway agent can't fire it dozens of times 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_scpi_query": {
      "limits": [
        {
          "counter": "vna_scpi_query_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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_scpi_query

What does the vna_scpi_query tool do? +

Send SCPI query and return response. It is categorised as a Execute tool in the Copper Mountain Vna MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on vna_scpi_query? +

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

vna_scpi_query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit vna_scpi_query? +

Yes. Add a rate_limit block to the vna_scpi_query 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_scpi_query completely? +

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

vna_scpi_query 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.