About Grim.Cards

Grim.Cards is an MTG deck simulator and evaluator built on the open-source Forge engine. Submit your Commander or Standard decklist, watch it run a full Gauntlet of AI-vs-AI matches, and receive a data-driven Power Score alongside detailed coaching insights.

Our mission

Most deck-testing advice is anecdotal. Grim.Cards replaces guesswork with simulation data — giving every player access to the kind of rigorous matchup analysis previously only available through expensive playtesting groups or professional tools.

The technology

Each simulation runs inside a modified Forge AI engine that plays thousands of individual game actions and records every decision. Our counterfactual learning system compares those decisions against alternatives, identifying which cards and play patterns consistently improve outcomes.

About the company

Grim.Cards was founded in 2026 by Steve Spencer and is based in Riverton, Utah, United States. Read the full company background.

Grim.Cards is an independent fan-created platform, not affiliated with, endorsed by, sponsored by, or approved by Wizards of the Coast LLC or Hasbro, Inc. Magic: The Gathering® is a trademark of Wizards of the Coast LLC.