bambu-p1s-mcp

Harness-agnostic MCP server for a Bambu Lab P1S on the local network.

Any MCP client can use it: Hermes, Grok, Claude Code, Cursor. The server speaks stdio (local subprocess) and Streamable HTTP (remote harness).

It does not talk to Bambu Cloud. It talks to the printer:

• MQTT over TLS, port 8883 — status and print commands

• Implicit FTPS, port 990 — list / upload files

• Optional Bambu Studio CLI — slice STL/3MF to a printable .gcode.3mf

Where to run it

The MCP process has to reach the printer. The agent harness does not.

If Hermes is on a DGX Spark that is not on the printer LAN, run this server on the LAN machine (or any box that can open 192.168.x.x:8883 and :990) and point Hermes at the HTTP URL. Grok on that same LAN box can use stdio.

This clone lives at /home/whaleshark/Documents/bambu-p1s-mcp. On the current LAN box the printer-facing IPs are typically:

• LAN: 192.168.1.195

• Tailscale: 100.123.149.116

Spark should use whichever of those it can route to, on port 8765.

P1S  <--- MQTT/FTPS ---  MCP host
                           |-- stdio --> harness on this host
                           |-- HTTP  --> Hermes on Spark / any remote MCP client

Related MCP server: Klipper MCP Server

Install

cd /home/whaleshark/Documents/bambu-p1s-mcp
uv sync --extra dev
cp .env.example .env
# fill BAMBU_IP, BAMBU_ACCESS_CODE, BAMBU_SERIAL from the printer screen
uv run bambu-p1s-mcp doctor

Printer screen: Settings → Network for IP and access code, Settings → Device for serial. Turn on LAN mode. Developer Mode if local project_file start is rejected.

Run

Stdio (Grok / Hermes on this machine):

uv run bambu-p1s-mcp

HTTP daemon (Hermes on Spark, or any remote client):

# bind LAN/Tailscale; set BAMBU_MCP_TOKEN in .env
BAMBU_MCP_HOST=0.0.0.0 uv run bambu-p1s-mcp --http
# health: http://<host>:8765/health
# mcp:    http://<host>:8765/mcp

User systemd unit: contrib/bambu-p1s-mcp.service.

Point a harness at it

Grok (~/.grok/config.toml), stdio:

[mcp_servers.bambu]
command = "/home/whaleshark/Documents/bambu-p1s-mcp/.venv/bin/bambu-p1s-mcp"
startup_timeout_sec = 45

Grok, HTTP (after the daemon is up):

[mcp_servers.bambu]
url = "http://127.0.0.1:8765/mcp"
headers = { Authorization = "Bearer ${BAMBU_MCP_TOKEN}" }

Hermes (~/.hermes/config.yaml) on Spark:

mcp_servers:
  bambu:
    url: "http://192.168.1.195:8765/mcp"
    headers:
      Authorization: "Bearer ${BAMBU_MCP_TOKEN}"
    timeout: 180

If Spark is only on Tailscale, use http://100.123.149.116:8765/mcp. Reload with /reload-mcp.

Ready-to-copy snippets: configs/.

Tools

Write tools require confirm=true. printer_print refuses if the printer is already RUNNING.

Ask an agent:

• “What’s on the P1S right now?”

• “Anything in the AMS?”

• “Slice ~/Documents/lamp/stls/base.stl for the P1S.”

• “Upload that 3mf and print plate 1.”

Slice notes

BAMBU_SLICER should point at the bambu-studio binary (this machine has /home/whaleshark/.local/bin/bambu-studio).

Project .3mf files that already contain printer settings can be sliced as-is. Bare STL/STEP needs machine + process + filament JSON. The server auto-discovers P1S 0.4 / 0.20mm Standard @BBL X1C / Bambu PLA Basic @BBL P1S 0.4 nozzle from ~/.config/BambuStudio/system/BBL when present.

Security

• LAN access code is the MQTT/FTPS password. Keep it in .env, not in git.

• HTTP without BAMBU_MCP_TOKEN is only for localhost. When Spark (or anything off-box) connects, set a token and bind BAMBU_MCP_HOST=0.0.0.0.

• Do not port-forward this to the public internet.

• This is not affiliated with Bambu Lab.

Goal

Agent brief: GOAL.md.