upload_print · Prusa MCP: Risk & Policy

WHAT IT DOES

What upload_print does on PrusaMCP

AI agents invoke upload_print to trigger actions in PrusaMCP. 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 upload_print needs a policy

This tool uploads a G-code file and triggers a 3D print job on physical hardware (OctoPrint or PrusaConnect). It not only writes a file but also initiates an external operation (starting a print), making it Execute. Misuse could cause unintended prints, wasted material, or hardware damage. Severity is high due to physical-world consequences.

From the tool's definition Upload un fichier G-code vers OctoPrint ou PrusaConnect pour lancer l' [impression]

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upload_print Rate-limited

upload_print 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": {
    "upload_print": {
      "limits": [
        {
          "counter": "upload_print_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 PrusaMCP, so you can run agents against it safely.

FAQ

Questions about upload_print

What does the upload_print tool do? +

Upload un fichier G-code vers OctoPrint ou PrusaConnect pour lancer l. It is categorised as a Execute tool in the PrusaMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on upload_print? +

Register the Prusa MCP server in PolicyLayer and add a rule for upload_print: 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 PrusaMCP. Nothing to install.

What risk level is upload_print? +

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

Can I rate-limit upload_print? +

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

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

upload_print is provided by the Prusa MCP server (noosbai/prusamcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.