Upload a .gcode, .3mf, or .stl file to the printer SD card via FTPS (port 990). Use printer_print_file to start the print after upload.
AI agents use ftp_upload_file to create or update resources in Bambu Lab MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Bambu Lab MCP Server environment.
The tool creates/stores new files on the printer's storage system. While uploads are reversible (files can be deleted), they modify the printer's state and could enable subsequent destructive or execute actions if malicious files are uploaded. However, the primary action is file creation/modification, making it Write rather than Execute or Destructive.
From the tool's definition Tool uploads files (.gcode, .3mf, .stl) to printer SD card via FTPS. Upload is a reversible data modification operation—files can be deleted or overwritten.
Documented attack patterns abuse exactly the kind of access ftp_upload_file gives an agent:
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 ftp_upload_file:
{
"version": "1",
"default": "deny",
"tools": {
"ftp_upload_file": {
"limits": [
{
"counter": "ftp_upload_file_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}ftp_upload_file 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.
Free to start. No card required.
Upload a .gcode, .3mf, or .stl file to the printer SD card via FTPS (port 990). Use printer_print_file to start the print after upload. 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.
Register the Bambu Lab MCP Server MCP server in PolicyLayer and add a rule for ftp_upload_file: 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.
ftp_upload_file is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the ftp_upload_file 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.
Set action: deny in the PolicyLayer policy for ftp_upload_file. 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.
ftp_upload_file 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.
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.
Free to start. No card required.
31 Bambu Lab MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.