record_jls · Joulescope MCP: Risk & Policy

WHAT IT DOES

What record_jls does on Joulescope

AI agents use record_jls to create or update resources in Joulescope — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Joulescope environment.

WHY IT NEEDS A POLICY

Why record_jls needs a policy

This tool writes raw measurement samples to a file on disk. It creates a new file (JLS v2 format) with captured data, which is a Write operation. It is not Destructive (no deletion), not Execute (no code execution), and not Financial. Severity is medium because it writes potentially large raw data files to the filesystem, and misuse could fill disk space or overwrite existing files.

From the tool's definition Record raw JS220 samples to a JLS v2 file for later waveform analysis

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

record_jls Rate-limited

record_jls 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": {
    "record_jls": {
      "limits": [
        {
          "counter": "record_jls_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 Joulescope, so you can run agents against it safely.

FAQ

Questions about record_jls

What does the record_jls tool do? +

Record raw JS220 samples to a JLS v2 file for later waveform analysis. It is categorised as a Write tool in the Joulescope MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on record_jls? +

Register the Joulescope MCP server in PolicyLayer and add a rule for record_jls: 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 Joulescope. Nothing to install.

What risk level is record_jls? +

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

Can I rate-limit record_jls? +

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

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

record_jls is provided by the Joulescope MCP server (juanqui/joulescope-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.