scope_arm · LeCroy Oscilloscope MCP: Risk & Policy

WHAT IT DOES

What scope_arm does on LeCroy Oscilloscope MCP

AI agents invoke scope_arm to trigger actions in LeCroy Oscilloscope MCP. 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 scope_arm needs a policy

The tool directly commands a physical instrument (LeCroy oscilloscope) to arm and begin active measurement operations. While not destructive or financial, arming a trigger initiates hardware-level state changes and measurement acquisition whose outcome depends on external conditions (input signals, trigger settings).

From the tool's definition Tool description states 'Arm the trigger (ARM). Start waiting for a trigger event.' - this triggers external hardware operations on a physical oscilloscope whose effects depend on the instrument state and signal conditions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

scope_arm Rate-limited

scope_arm 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": {
    "scope_arm": {
      "limits": [
        {
          "counter": "scope_arm_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 LeCroy Oscilloscope MCP, so you can run agents against it safely.

FAQ

Questions about scope_arm

What does the scope_arm tool do? +

Arm the trigger (ARM). Start waiting for a trigger event. It is categorised as a Execute tool in the LeCroy Oscilloscope MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on scope_arm? +

Register the LeCroy Oscilloscope MCP server in PolicyLayer and add a rule for scope_arm: 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 LeCroy Oscilloscope MCP. Nothing to install.

What risk level is scope_arm? +

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

Can I rate-limit scope_arm? +

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

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

scope_arm is provided by the LeCroy Oscilloscope MCP server (lucasgerads/lecroy-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.