restore_config · Cnc Fluidnc MCP: Risk & Policy

WHAT IT DOES

What restore_config does on Cnc Fluidnc

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

WHY IT NEEDS A POLICY

Why restore_config needs a policy

This tool modifies machine state by restoring (overwriting) CNC machine settings from a backup file. While reversible in principle (settings can be backed up again), it changes critical machine configuration that could affect CNC operation, safety, and calibration. It is Write rather than Destructive because the operation is reversible and the tool includes a dry-run mode by default for safety.

From the tool's definition Tool description states 'Restore machine settings from a backup' and 'apply' the restoration when confirm=true is provided. This modifies machine configuration settings.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

restore_config Rate-limited

restore_config 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": {
    "restore_config": {
      "limits": [
        {
          "counter": "restore_config_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 Cnc Fluidnc, so you can run agents against it safely.

FAQ

Questions about restore_config

What does the restore_config tool do? +

Restore machine settings from a backup. Defaults to dry-run mode showing what would change. Requires confirm=true to actually apply. It is categorised as a Write tool in the Cnc Fluidnc MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on restore_config? +

Register the Cnc Fluidnc MCP server in PolicyLayer and add a rule for restore_config: 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 Cnc Fluidnc. Nothing to install.

What risk level is restore_config? +

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

Can I rate-limit restore_config? +

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

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

restore_config is provided by the Cnc Fluidnc MCP server (whitneydesignlabs/cnc-fluidnc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.