The 10 Commandments of Magic: the Gathering Deck Building

You've been playing Magic: the Gathering for a while. You understand the rules, you've cracked a few packs, and you've probably lost to a deck so efficiently cruel that it made you question your life choices. Welcome to the levelling-up phase — where the game stops being about knowing how to play and starts being about knowing how to build.

These are the 10 Commandments. Not suggestions. Commandments. Burn them in. Your future opponents will feel it.

I. Thou Shalt Know Thy Win Condition

Before you sleeve a single card, answer this question: how does this deck win? Not "it deals damage" or "it controls things." Specifically. Does it combo off on turn four? Does it grind opponents into dust with card advantage? Does it flood the board and swing for lethal?

If you can't answer that in one sentence, your deck doesn't have a win condition — it has a collection of cards with vague intentions. Those decks lose.

II. Thou Shalt Respect the Mana Curve

Your mana curve is the heartbeat of your deck. Plot out the converted mana costs of every card and you'll see a shape — ideally a curve that peaks low and tapers off. Aggro decks want most of their spells at one or two mana. Midrange peaks around three. Control can afford to go higher, but only because it's buying time.

A curve that's all over the place is a deck that'll sit in your hand on the turns you need to be doing things. Smooth it out.

III. Thou Shalt Not Covet Thy Rare Slots

Here's a trap every improving player falls into: cramming four copies of every exciting rare because the cards are individually powerful. The result is a deck that's objectively impressive and practically unplayable — wildly inconsistent, impossible to curve out, and expensive for no good reason.

Rares earn their slots by serving the deck's strategy. If a card doesn't advance your win condition, cut it. Doesn't matter how much you spent on it.

IV. Thou Shalt Run Enough Lands

This one has a number: 24 in most 60-card decks. You can go to 22 if your curve is aggressively low. You can go to 26 if you're running a greedy control or ramp shell. But 20 lands because "I want more spells" is how you lose to yourself before your opponent gets a turn.

Mana drought (too few lands) and mana flood (too many) are real. Respect the math.

V. Thou Shalt Value Card Advantage

Card advantage means having more cards than your opponent — either by drawing more or by making each card count for more than one. It's arguably the most important concept in Magic, and improving players tend to underestimate it completely.

A 2-for-1 (one card that handles two of your opponent's cards, or replaces itself while doing something else) is almost always worth running. Cards that do nothing without other cards? Think carefully. Card disadvantage — trading down, depleting your hand — loses games at a slow, grinding pace you don't even notice until it's too late.

VI. Thou Shalt Build a Sideboard With Purpose

Your sideboard (the 15 cards outside your main deck that you can swap in between games two and three) is not a dumping ground for cards that didn't make the cut. It's a surgical toolkit.

Ask yourself: what does my deck struggle against? Aggro? Run sweepers. Graveyard strategies? Bring hate (cards specifically designed to disrupt graveyard play). Big mana and ramp decks? Pack some disruption. A good sideboard is a plan. A bad sideboard is wishful thinking.

VII. Thou Shalt Not Chase the Meta Blindly

The meta (the current competitive landscape — which decks are dominant, which strategies are trending) matters. Ignoring it entirely is naive. But copying the top deck card-for-card without understanding why it works is almost as bad.

Understand the meta. Then decide how your deck interacts with it. Are you playing the top deck? Playing something that beats the top deck? Playing something that doesn't care what the top deck does? All three are valid strategies. "I just put in the cards that are expensive" is not.

VIII. Thou Shalt Test Before Thou Buys

This is the one that'll save you the most money. Before you drop real cash on a decklist you found online, proxy it (make rough paper copies of the cards) and play it. Ten games minimum. You'll quickly discover whether you actually enjoy piloting it, whether it performs the way you expected, and which cards are dead weight.

Buying first, testing second is how you end up with a $400 deck you hate playing.

IX. Thou Shalt Cut Ruthlessly

Your first draft of any deck will be too many cards trying to do too many things. The hardest skill in deck building isn't knowing what to add — it's knowing what to cut.

The question to ask every card: does this advance my strategy better than the card I'd cut to make room for it? If the answer is no, it's out. Sentiment is not a deck-building criterion. That card your friend gave you that you love — cut it if it doesn't fit. You can love it from the binder.

X. Thou Shalt Iterate

No deck is finished. The best deck builders in the world treat their lists as living documents — constantly refining, testing, adjusting one or two cards at a time based on what they're seeing across the table.

After every session, ask yourself: what did I wish I had drawn more of? What sat dead in my hand? What did I sideboard out every single game two (because if you always board it out, it shouldn't be in the main deck)? Small, deliberate tweaks compound into a dramatically better deck over time.

Build. Play. Learn. Repeat.

The Bottom Line

Great decks don't happen by accident. They're built with intention, refined through repetition, and sharpened by honest self-assessment. The players who improve fastest aren't the ones who open the most packs — they're the ones who think hardest about why their decks win and lose.

That's exactly what we built Summon Agents for. Our AI deck builder doesn't just assemble cards — it analyses your list against these fundamentals, spots the weaknesses, and helps you iterate faster than you ever could alone.

The commandments are yours. Now go build something dangerous.

— Lore.exe

Ready to put these principles into action? Fire up the Summon Agents deck builder and let the AI do the heavy lifting on your next list.