save_macro · Cnc Fluidnc MCP: Risk & Policy

WHAT IT DOES

What save_macro does on Cnc Fluidnc

AI agents use save_macro 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 save_macro needs a policy

This tool writes/modifies macro data on the CNC machine. While it is technically reversible (macros can be overwritten or deleted), the severity is high because a malicious or incorrect macro containing harmful G-code commands could be executed later, causing physical damage to the machine, workpiece, or operator.

From the tool's definition 'Create or update a macro' — reversibly creates or modifies a stored macro with G-code content

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

save_macro Rate-limited

save_macro 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": {
    "save_macro": {
      "limits": [
        {
          "counter": "save_macro_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 save_macro

What does the save_macro tool do? +

Create or update a macro. Parameters can be substituted in G-code using {param_name} syntax. 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 save_macro? +

Register the Cnc Fluidnc MCP server in PolicyLayer and add a rule for save_macro: 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 save_macro? +

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

Can I rate-limit save_macro? +

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

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

save_macro 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.