PrintPal

🖨️ PrintPal

AI-powered 3D printing assistant — search, slice, and print from your terminal.

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What is PrintPal?

PrintPal is a terminal-based 3D printing assistant. You type what you want to print in plain English, and an AI agent handles the rest — searching Thingiverse, downloading models, slicing them with CuraEngine, and sending them to your OctoPrint server.

It's like having a 3D printing expert sitting next to you, ready to find and prepare prints without you ever touching a slicer.

The pipeline

🗣️  You: "find and download a benchy"
         ↓
🔍  Agent searches Thingiverse
         ↓
📥  Downloads the STL (stored in the database)
         ↓
🔪  You: /slice 1                    ← instant, no AI tokens spent
         ↓
🖨️  You: /print 2                    ← preheats, uploads, starts

✨ Features

• Natural language search — just describe what you want to print
• Self-contained storage — all models and G-code stored as BLOBs in SQLite, no external files
• Direct slicing — /slice <id> runs CuraEngine or OrcaSlicer instantly, zero AI tokens
• Full print pipeline — /print <id> preheats, uploads to OctoPrint, and starts
• Permission system — control what the agent can do (Manual / Auto / Bypass modes)
• Session management — save/load conversations with full memory and prompt history
• Live monitoring — /print status shows real-time temps and job progress
• Cost tracking — /cost shows token usage and estimated dollar cost
• Print queue — queue prints when the printer is busy
• DB backups — /backup snapshots your entire database
• Settings management — /config to view and set OctoPrint URL, API keys, etc.

🚀 Quick start

Prerequisites

• Python 3.10+
• uv — dependency manager
• Ultimaker Cura — for slicing (auto-detected)
• An OctoPrint server — for printing (optional, only needed for Level 3)
• An Anthropic API key — for the AI agent (Claude Sonnet)

Setup

# Clone the repo
git clone <repo-url>
cd PrintPal

# Copy the example config and add your keys
cp .env.example .env
# Edit .env — add your ANTHROPIC_API_KEY and THINGIVERSE_TOKEN

# Run it!
uv run printpal

You'll see the PrintPal banner with a random tip:

┌───────────────────────────────── PrintPal ──────────────────────────────────┐
│ PrintMCP: connected (14 tools)                                              │
│ model: claude-sonnet-4-6                                                    │
│ tip: Type a natural language request like 'find and download a benchy'...   │
└─────────────────────────────────────────────────────────────────────────────┘
PrintPal  no things  model: claude-sonnet-4-6  mcp: 14 tools  mode: manual
> find and download a benchy

Configuration

Settings can be stored in .env (for initial setup) or managed at runtime with /config (stored in the database, overrides .env):

# Inside PrintPal:
/config set octoprint_url http://192.168.1.50
/config set octoprint_api_key your-api-key-here
/config set thingiverse_token your-thingiverse-token
/config set auto_save true          # auto-save sessions after each prompt

Setting	Environment variable	Required for	Masked?
thingiverse_token	THINGIVERSE_TOKEN	Searching & downloading	Yes
octoprint_url	OCTOPRINT_URL	Printing	No
octoprint_api_key	OCTOPRINT_API_KEY	Printing	Yes
cura_dir	PRINTMCP_CURA_DIR	Slicing (Cura; auto-detected)	No
auto_save	—	Optional convenience	No

🎮 Commands

Session management

Command	Description
/save [name]	Save the current session (auto-names if no name given)
/load <name|id>	Load a saved session by name or numeric ID
/sessions	List all saved sessions
/new	Clear the session and start fresh (alias: /clear)
/cost	Show token usage and estimated cost for this session
/exit	Exit PrintPal (aliases: /quit, /q)

Things (downloaded models & G-code)

Command	Description
/thing	List all things in the database
/thing <id>	Show details for a specific thing
/thing export <id> [dest]	Write a thing's file back to disk
/thing delete <id>	Remove a thing from the database

Slicing

/slice uses whichever slicer you have. OrcaSlicer is preferred when both are installed; force one with --slicer cura|orca.

Command	Description
/slice <id>	Slice a model to G-code (auto-detected slicer)
/slice <id> --slicer cura	Force CuraEngine for this slice
/slice <id> --slicer orca	Force OrcaSlicer for this slice
/slice <id> --layer-height 0.12	Set layer height (0.05–0.6mm)
/slice <id> --infill 40 --supports	Set infill % and enable supports
/slice <id> --printer creality_ender3pro	Set printer profile (Cura)
/slice <id> --temp 210 --bed 65	Set nozzle and bed temperatures
/slice <id> --adhesion brim	Set adhesion type (skirt/brim/raft/none)

Short flags: --lh, --inf, --sup, --ad, --t, --b, --p, --sl

For OrcaSlicer, PrintPal uses its 3-tier presets (machine / process / filament). Defaults assume an Ender-3 Pro with a 0.4 nozzle; point them at your machine and material via /config:

/config set slicer orca                                   # prefer OrcaSlicer always
/config set orca_machine "Creality Ender-3 Pro 0.4 nozzle"
/config set orca_process "0.20mm Standard @Creality Ender3 Pro 0.4"
/config set orca_filament "Creality Generic PLA"

Find preset names with the PrintMCP orca_list_profiles tool (or ask the agent: "list my OrcaSlicer machine presets").

Printers

A printer preset bundles everything the slicers need for one machine — the Cura definition id and the OrcaSlicer machine/process/filament presets — under one name. /printer use <name> applies the bundle so /slice (and the agent) slice for that printer. A default ender-3-pro preset ships with the app.

Command	Description
/printer or /printer list	List presets (marks the active one with ●)
/printer show [name]	Show one preset's slicer settings (no arg = active)
/printer use <name>	Activate a preset — applies it to slicing
/printer add <name> [options]	Save a preset. Options: --cura <id> --machine <m> --process <p> --filament <f>
/printer remove <name>	Delete a preset

Adding with no options pre-fills from the Ender-3 Pro defaults so you can tweak from a working baseline. Names with spaces work either quoted or unquoted (the command joins the remaining words):

/printer add "Voron 2.4" --machine "Voron 2.4 0.4 nozzle" --process "0.20mm Standard" --filament "Generic PLA"
/printer use Voron 2.4
/slice 1

Printing

Command	Description
/print <id>	Full pipeline: check → connect → preheat → upload → start
/print <id> --no-preheat	Skip preheating, let G-code handle temps
/print status	Live auto-refreshing printer status (Ctrl+C to stop)
/print pause	Pause the active print
/print resume	Resume the paused print
/print cancel	Cancel the print (G-code is kept for reprinting)
/print connect	Connect to the printer
/print disconnect	Disconnect from the printer
/print files	List G-code files on the OctoPrint server
/print queue	Show the print queue
/print queue remove <pos>	Remove an item from the queue
/print queue clear	Clear the entire queue

Permissions

Command	Description
/mode	Show current mode and tool categories
/mode default	Manual — ask for every tool call
/mode auto	Auto — approve searches/downloads, ask before physical actions
/mode bypass	Bypass — approve everything (with warning)

Shift+Tab cycles between Manual and Auto modes.

When the agent calls a tool, you'll see:

┌─ Permission Required ──────────────────────────┐
│ Tool:     thingiverse_search_models            │
│ Category: Read-only                            │
│ [y] Yes  [n] No  [a] Always allow this tool  │
└────────────────────────────────────────────────┘

App management

Command	Description
/config	Show all settings (API keys masked)
/config set <key> <value>	Set a setting
/config get <key>	Show one setting (unmasked)
/config unset <key>	Delete a setting
/logs	Show recent logs (last 20)
/logs 50	Show last N logs
/logs error	Show only errors
/logs clear	Clear all logs
/backup	Create a database backup
/backup list	List backups
/backup restore <name>	Restore from a backup
/redraw	Clear and redraw the UI (use after terminal resize)
/self-destruct	Delete ALL data — database, backups, everything. Irreversible.
/help	Show all available commands

🏗️ Architecture

src/printpal/
├── __init__.py              # Package marker
├── __main__.py              # python -m printpal entry point
├── app.py                   # Main REPL loop, bootstrap, command dispatch
├── config.py                # MODEL_ID, settings mapping, tips, examples
├── ui.py                    # Shared console, accent color, format helpers, progress bars
├── db.py                    # SQLite layer (sessions, things, queue, settings, logs, backups)
├── sessions.py              # Session save/load (agent memory + prompt history)
├── permissions.py           # Permission system (ApprovalMode, PermissionTool wrapper)
├── scanner.py               # Download + slice scanner (captures files into BLOBs)
├── completer.py             # Command autocomplete (prefix matching)
├── pricing.py               # Model pricing data for /cost
└── commands/                # All /slash command implementations
    ├── __init__.py           # Re-exports all cmd_* functions + COMMANDS dict
    ├── helpers.py            # Shared utilities (tool lookup, slice flags, preheat)
    ├── session.py            # /save, /load, /sessions
    ├── thing.py              # /thing, /slice
    ├── print.py              # /print and all sub-commands
    ├── mode.py               # /mode
    ├── admin.py              # /config, /cost, /logs, /backup
    └── help.py               # /help

PrintPal connects to PrintMCP — an MCP server that provides the 3D printing tools:

• Level 1 (Thingiverse) — search, inspect, download 3D models
• Level 2 (Cura) — slice models into G-code via CuraEngine
• Level 3 (OctoPrint) — upload, print, monitor, control

The AI agent (powered by smolagents + LiteLLM) uses these tools autonomously. Slash commands like /slice and /print call the tools directly — no AI tokens spent.

Developing against a local PrintMCP

By default PrintPal launches the published PrintMCP package (uvx printmcp). To develop both repos together — e.g. you're editing PrintMCP's tools and want PrintPal to use your local checkout — set PRINTPAL_PRINTMCP_COMMAND to the launch command before starting PrintPal:

# Point PrintPal at your local PrintMCP checkout:
export PRINTPAL_PRINTMCP_COMMAND="uv run --directory /path/to/PrintMCP printmcp"
uv run printpal

or, from any venv that already has printmcp installed:

export PRINTPAL_PRINTMCP_COMMAND="python -m printmcp"

The value is split with shlex, so quoted paths with spaces work. Which server you're talking to is shown in the startup banner — pypi (uvx printmcp) by default or local (<your command>) when overridden. Unset the variable to go back to the PyPI release.

Database

Everything is stored in a single SQLite file at ~/.printpal/printpal.db:

Table	What it stores
sessions	Agent memory, prompt history, permissions per session
things	Downloaded models and sliced G-code (as BLOBs)
print_queue	Queued print jobs
settings	App configuration (OctoPrint URL, API keys, etc.)
logs	Error and info logs
scanned_steps	Tracks which agent steps have been processed for downloads

Backups are stored at ~/.printpal/backups/.

🔧 Troubleshooting

Problem	Solution
MCP server didn't respond in time	Ensure uvx printmcp works: run uvx printmcp --version
THINGIVERSE_TOKEN is not set	Run /config set thingiverse_token <token> or add to .env
OCTOPRINT_URL and OCTOPRINT_API_KEY not set	Run /config set octoprint_url <url> and /config set octoprint_api_key <key>
CuraEngine not found	Install Ultimaker Cura, or set PRINTMCP_CURA_DIR via /config set cura_dir <path>
orca_slice_model tool not found	Install OrcaSlicer (native or Flatpak), or slice with Cura: /slice <id> --slicer cura
Permission denied on every tool call	Switch to auto mode: /mode auto or press Shift+Tab
uv not found	Install uv: pip install uv or see uv docs

📋 Requirements

• Python ≥ 3.10
• uv for dependency management
• PrintMCP — installed automatically via uvx
• Ultimaker Cura — for slicing (Level 2)
• OctoPrint server — for printing (Level 3)
• Anthropic API key — for the AI agent (Claude Sonnet)

📄 License

Licensed under the MIT License — © 2026 SourceBox LLC.

You may freely use, modify, and distribute this software, provided you retain the copyright and license notice.

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Built with smolagents, PrintMCP, Rich, and prompt_toolkit.