go_to_zero · Cnc Fluidnc MCP: Risk & Policy

WHAT IT DOES

What go_to_zero does on Cnc Fluidnc

AI agents invoke go_to_zero to trigger actions in Cnc Fluidnc. 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 go_to_zero needs a policy

This tool triggers physical machine motion on a CNC router — raising/lowering the Z axis and moving XY axes. It executes a multi-step movement sequence on physical hardware. Misuse could cause collisions, tool breakage, or workpiece damage (e.g., if safe height is insufficient or coordinates are wrong), making it high severity.

From the tool's definition Move to work coordinate zero. Raises Z to safe height first, then moves XY, then lowers Z.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

go_to_zero Rate-limited

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

FAQ

Questions about go_to_zero

What does the go_to_zero tool do? +

Move to work coordinate zero. Raises Z to safe height first, then moves XY, then lowers Z. It is categorised as a Execute tool in the Cnc Fluidnc MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on go_to_zero? +

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

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

Can I rate-limit go_to_zero? +

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

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

go_to_zero 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.