Bambu Lab MCP Server

Model Context Protocol server for Bambu Lab 3D printers

Full control of Bambu Lab printers through Claude AI — MQTT, FTP, camera, AMS, and X.509 auth

Features · Quick Start · Tools · Background

Overview

Complete MCP server for Bambu Lab 3D printers (P1P, P1S, X1C, A1, A1 Mini). Connects over local MQTT for real-time control and monitoring, with FTPS file upload and X.509 certificate signing to bypass firmware authentication restrictions.

25 tools covering print control, status monitoring, camera, AMS filament management, temperature, LED control, and more.

Background

In January 2025, Bambu Lab pushed firmware updates requiring authentication for local LAN printer control, breaking all third-party tools — OctoPrint, Home Assistant integrations, custom scripts, everything.

Community researchers extracted the X.509 certificate and private key from the Bambu Connect desktop application, restoring third-party access. This MCP server builds on that work to provide comprehensive printer control through Claude.

Key references:

Hackaday: Bambu Connect's Authentication X.509 Certificate and Private Key Extracted — the article that started the workaround
OpenBambuAPI — reverse-engineered MQTT protocol documentation
bambu-node — TypeScript library for Bambu printers

Features

Local MQTT control — Print, pause, resume, stop, speed profiles, G-code execution
Real-time status — Continuous caching from MQTT reports with cached + fresh status tools
Camera control — Start/stop recording and timelapse
AMS management — Change filament trays, unload filament
FTP file upload — FTPS upload to printer SD card (port 990)
X.509 signing — Bypass firmware auth restrictions with certificate signing
Temperature control — Set nozzle/bed temps with safety limits
Object skipping — Skip failed objects without stopping the print
Speed profiles — Silent, Standard, Sport, Ludicrous (or raw percentage)
LED control — Chamber and work lights
Safety validation — Blocked G-codes, temperature limits, path traversal prevention

Quick Start

Prerequisites

Node.js 18+
Bambu Lab printer on your local network
Printer LAN access code (printer screen -> WLAN -> Access Code)
Printer serial number (Settings -> Device -> Serial Number)

Install

git clone https://github.com/schwarztim/bambu-mcp.git
cd bambu-mcp
npm install
npm run build

Configure

cp .env.example .env
# Edit .env with your printer IP, access code, and serial number

Register with Claude Code

Add to ~/.claude/user-mcps.json:

{
  "mcpServers": {
    "bambu-lab": {
      "command": "node",
      "args": ["/path/to/bambu-mcp/dist/index.js"],
      "env": {
        "BAMBU_LAB_MQTT_HOST": "192.168.1.100",
        "BAMBU_LAB_MQTT_PASSWORD": "YOUR_ACCESS_CODE",
        "BAMBU_LAB_DEVICE_ID": "YOUR_SERIAL_NUMBER"
      }
    }
  }
}

Tools

Cloud API (4 tools)

Tool	Description
`get_user_profile`	Get Bambu Lab cloud account profile
`list_printers`	List all printers registered to cloud account
`get_printer_status`	Get printer status via cloud API
`sign_message`	Sign message with X.509 certificate for firmware auth bypass

Print Control (7 tools)

Tool	Description
`printer_stop`	Stop the current print immediately
`printer_pause`	Pause the current print
`printer_resume`	Resume a paused print
`printer_set_speed`	Set speed via profile (silent/standard/sport/ludicrous) or percentage
`printer_send_gcode`	Send G-code command (dangerous commands blocked)
`printer_print_file`	Start printing a file from printer SD card
`skip_objects`	Skip specific objects during multi-object prints

Status & Info (3 tools)

Tool	Description
`printer_get_status`	Request full status push (temps, progress, AMS, fans, etc.)
`printer_get_cached_status`	Return last cached status (no pushall — use for frequent polling)
`printer_get_version`	Get firmware and module version info

Camera (2 tools)

Tool	Description
`camera_record`	Enable/disable camera recording
`camera_timelapse`	Enable/disable timelapse recording

AMS & Filament (2 tools)

Tool	Description
`ams_change_filament`	Change to a different AMS tray (0-3)
`ams_unload_filament`	Unload current filament from extruder

Hardware (3 tools)

Tool	Description
`set_temperature`	Set nozzle or bed temperature (with safety limits)
`set_nozzle`	Set nozzle diameter for profile selection
`led_control`	Control chamber/work LED lights

Connection & Upload (3 tools)

Tool	Description
`mqtt_connect`	Connect to printer via local MQTT over TLS
`mqtt_disconnect`	Disconnect from MQTT
`ftp_upload_file`	Upload .gcode/.3mf/.stl to printer via FTPS

Architecture

Claude Code / AI
    |
    v
Bambu Lab MCP Server
  |-- Cloud API (bambulab.com)
  |-- MQTT Client (port 8883, TLS)
  |-- FTP Client (port 990, FTPS)
    |
    v
Bambu Lab Printer (P1P/P1S/X1C/A1)

How It Works

MQTT connects to the printer over TLS on port 8883 using the LAN access code
Status reports are continuously cached as they arrive on the MQTT report topic
Commands are sent on the MQTT request topic with sequence IDs for response matching
FTP uploads files to the printer SD card over FTPS (port 990)
X.509 signing uses the extracted Bambu Connect certificate for authenticated commands

Configuration

Environment Variables

Variable	Required	Description
`BAMBU_LAB_MQTT_HOST`	For MQTT	Printer IP address
`BAMBU_LAB_MQTT_PASSWORD`	For MQTT	LAN access code
`BAMBU_LAB_DEVICE_ID`	For MQTT	Printer serial number
`BAMBU_LAB_MQTT_PORT`	No	MQTT port (default: 8883)
`BAMBU_LAB_MQTT_USERNAME`	No	MQTT username (default: bblp)
`BAMBU_LAB_COOKIES`	For cloud	Session cookies for cloud API
`BAMBU_LAB_BASE_URL`	No	Cloud API base URL
`BAMBU_APP_PRIVATE_KEY`	No	Override the built-in X.509 private key
`BAMBU_APP_CERTIFICATE`	No	Override the built-in X.509 certificate

Finding Your Printer Info

IP Address: Printer screen → WLAN → IP
Access Code: Printer screen → WLAN → Access Code (8-digit)
Serial Number: Settings → Device → Serial Number

Security

X.509 Certificate

This server includes the publicly extracted X.509 certificate from the Bambu Connect desktop application. This is not a secret — it was publicly disclosed in January 2025 and is embedded in every copy of Bambu Connect.

The certificate can be overridden via BAMBU_APP_PRIVATE_KEY and BAMBU_APP_CERTIFICATE environment variables if Bambu Lab rotates credentials.

Safety Features

Blocked G-codes: M112 (emergency stop), M502 (factory reset), M500/M501 (EEPROM), M997 (firmware update), M999 (restart)
Temperature limits: Nozzle max 300C, bed max 120C
File validation: Only .gcode, .3mf, .stl uploads allowed
Path traversal prevention: No .. or absolute paths in FTP uploads

Best Practices

Keep printers on a separate VLAN
Rotate LAN access codes periodically
Never commit .env files (already in .gitignore)

Acknowledgments

Community researchers who extracted the X.509 certificate — making this possible
OpenBambuAPI — reverse-engineered MQTT protocol docs
Shockedrope/bambu-mcp-server — speed profile concept
DMontgomery40/mcp-3D-printer-server — multi-printer platform inspiration
bambu-node — TypeScript Bambu library
Bambu Lab — for making excellent printers (even if the auth lockdown was rough)

License

MIT — see LICENSE for details.

Disclaimer

Not affiliated with or endorsed by Bambu Lab. Use at your own risk.

bambu-mcp