usbtmc_query · USBTMC MCP Server MCP: Risk & Policy

WHAT IT DOES

What usbtmc_query does on USBTMC MCP Server

AI agents invoke usbtmc_query to trigger actions in USBTMC MCP Server. 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 usbtmc_query needs a policy

In USBTMC/SCPI contexts, a 'query' operation typically sends a command to the instrument and reads back the response — it executes an operation on external hardware. Since the description is empty, confidence is reduced, but given the server context (controlling measurement devices via SCPI), this likely triggers instrument actions.

From the tool's definition Tool name 'usbtmc_query' on a server that sends SCPI commands to test and measurement devices; sibling tools include 'usbtmc_send' and 'usbtmc_receive', suggesting query combines send+receive

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

usbtmc_query Rate-limited

usbtmc_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": {
    "usbtmc_query": {
      "limits": [
        {
          "counter": "usbtmc_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 USBTMC MCP Server, so you can run agents against it safely.

FAQ

Questions about usbtmc_query

What does the usbtmc_query tool do? +

usbtmc_query. It is categorised as a Execute tool in the USBTMC MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on usbtmc_query? +

Register the USBTMC MCP Server MCP server in PolicyLayer and add a rule for usbtmc_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 USBTMC MCP Server. Nothing to install.

What risk level is usbtmc_query? +

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

Can I rate-limit usbtmc_query? +

Yes. Add a rate_limit block to the usbtmc_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 usbtmc_query completely? +

Set action: deny in the PolicyLayer policy for usbtmc_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 usbtmc_query? +

usbtmc_query is provided by the USBTMC MCP Server MCP server (naonaome/usbtmc-lite-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.