set_nozzle

THE RISK

Medium Risk

Why set_nozzle needs a policy

This tool writes/modifies printer hardware configuration (nozzle diameter setting). While the change is reversible and doesn't delete data or move money, it alters the printer's operational parameters, affecting future print quality and behavior.

From the tool's definition The tool 'set_nozzle' modifies the nozzle diameter setting on the 3D printer hardware, which is a configuration change that affects subsequent print jobs.

Documented attack patterns abuse exactly the kind of access set_nozzle gives an agent:

POLICY

How to control set_nozzle

PolicyLayer is an MCP gateway — it sits between your AI agents and Bambu Lab MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for set_nozzle:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_nozzle": {
      "limits": [
        {
          "counter": "set_nozzle_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

set_nozzle 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.

Create a free account and register Bambu Lab MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about set_nozzle

What does the set_nozzle tool do? +

Set the nozzle diameter (for printing profile selection). It is categorised as a Write tool in the Bambu Lab MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_nozzle? +

Register the Bambu Lab MCP Server MCP server in PolicyLayer and add a rule for set_nozzle: 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 Bambu Lab MCP Server. Nothing to install.

What risk level is set_nozzle? +

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

Can I rate-limit set_nozzle? +

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

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

set_nozzle is provided by the Bambu Lab MCP Server MCP server (schwarztim/bambu-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Bambu Lab MCP Server tool call.

Start from Bambu Lab MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →