Commander Deck Check
A desktop app that checks a Magic Commander deck against the rules and against your own collection.
- What
- Desktop tool, open source
- Status
- Open source, MIT licence
- Stack
- Python, Tkinter, MTGJSON, Scryfall, EDHREC
What it is
A desktop app for Magic: The Gathering's Commander format. You give it a deck list and a commander, and it tells you:
- whether the deck follows the Commander rules: exactly 100 cards, a legal commander, and colour identity respected;
- which commanders you could build around with the cards you already own;
- EDHREC suggestions for your commander;
- current card prices from Scryfall.
Card data comes from MTGJSON's full printings file, so it knows every printing and format.
How I built it
I built it with Gemini CLI, writing the tool through an AI coding agent, and later extended it with Claude Code.
Interesting bits
- The UI stays responsive. The large data file loads on a background thread, and long checks can be stopped with a Stop button.
- Prices are cached (12 hours by default, adjustable in the settings), so repeated checks don't hit Scryfall again.
- Real-world data fixes. Accented card names are normalized before they go into EDHREC URLs, which used to return 403 errors. Double-faced cards get the right URL.
- Ships as a single executable. A PyInstaller script builds it for Linux, with instructions for a Windows build.