How to upgrade Keen Engineering, the Sai precon

Keen Engineering already out-draws every deck in the box. It needs cheaper artifacts and a real finish: ten swaps for $12.37, upgrades at three budgets, and how Sai closes a game.

Aymeric Lamontagne

Nov 2, 2026

When we ranked the five Foundations Commander decks in September, Keen Engineering came third: the best engine in the box and the weakest closer of the top three. Three weeks after release, that still reads right, and it points straight at the upgrade. So here is the honest finding up front: this deck does not need more card draw. It already has the most in the box. It needs cheaper things to cast, and a way to end the game.

The number that explains it: of the deck's 43 nonland artifacts, none costs zero mana and only three cost one. Sai, Master Thopterist pays you per artifact spell, not per mana spent, so a five-mana artifact and a free one make exactly the same Thopter. The precon is built as if that were not true. The ten-card package at the end of this piece fixes most of it, and it came to $12.37 in singles on October 23, 2026 — not one card in it costs more than $3.49.

This piece covers four things, in order: how Sai actually works and what the 99 is doing around him, the ten cards to cut, the cards to add at three budgets, and how an upgraded list closes a game — including what to do when someone casts a board wipe into a table full of Thopters.

Swaps

10 — Out of the 99

Package cost

$12.37 — All ten adds

Artifacts at 0–1 mana

3 → 8 — Before and after

Game Changers added

0 — Still Bracket 2 by the list

The upgrade at a glance. Counts from the printed decklist checked against Manamancer’s card index; prices are the cheapest English non-Foundations-Commander printing in that index, refreshed October 23, 2026.

What Sai is really doing

• Sai, Master Thopterist — 2U · 1/4 Human Artificer · mono-blue

Sai, Master Thopterist has two lines of text, and they are two halves of one machine. The first — whenever you cast an artifact spell, create a 1/1 flying Thopter — turns every artifact into two artifacts. The second — {1}{U}, sacrifice two artifacts: draw a card — turns any two artifacts back into a card. Put together, Sai is a converter: artifact spells go in, fliers and cards come out, and the exchange rate is set by how cheap the artifacts are.

The trigger counts casts, not mana. That is the whole upgrade in one sentence. A free artifact cast with Sai on the table is a free 1/1 flier; cast with Vedalken Archmage out as well, it is also a free card. The deck's cost reducers — Etherium Sculptor, Foundry Inspector — make that true of more cards, and the affinity cards (Thoughtcast, Thought Monitor, Broodstar) get cheaper as the Thopters pile up, because a Thopter token is an artifact too. The engine wants a lot of very cheap casts, and the list gives it eight artifacts at six mana or more instead.

The sacrifice is the card-flow half. Two artifacts for a card is a poor rate for a Darksteel Juggernaut. It is a very good rate for a Thopter you got for free and a Mind Stone you no longer need, and it is an excellent rate for an artifact that draws a card of its own when it hits the graveyard. Sai's sacrifice is also instant speed, which matters later: an artifact about to be destroyed is, with {1}{U} up, half a card instead of nothing.

Around him the 99 does three jobs. It draws — Archmage, Thopter Spy Network, Padeem, Consul of Innovation, Shimmer Dragon, Research Thief and the rest make this the best card-draw deck in the box by a distance. It defends — Propaganda, Counterspell, Negate, Aetherize. And it tries to win with a pile of fliers made large by Forsaken Monument, Master of Etherium, Chief of the Foundry and Steel Overseer. The first two jobs are done well. The third is where the upgrade goes.

What to cut

Ten cards, chosen by one test: does it make Sai's conversion cheaper, does it end the game, or does it protect the board that does? These do none of the three well. Not one of them was worth more than a dollar as a single on October 23 — you are not giving up anything you would sell.

The ten cuts

• Spire Golem — A 2/4 flier with no other text, in a deck that makes fliers for free. Its affinity counts Islands, not artifacts.
• Memory Guardian — A vanilla 3/4 flier. Affinity makes it cheap; nothing makes it matter.
• Darksteel Juggernaut — Must attack every combat, on the ground — so it can neither fly over a board nor stay home behind Propaganda.
• Cultivator's Caravan — A three-mana rock whose colour fixing a mono-blue deck has no use for.
• Hedron Archive — Four mana for two colourless, in a list already running 40 lands and nine other rocks and dorks.
• Mind's Eye — Five mana, then one more per card. The deck out-draws the table without it.
• Nevinyrral's Disk — Destroys every artifact on the table — which is to say, your deck. All Is Dust is the sweeper that fits.
• Launch Mishap — Three mana to counter only a creature or planeswalker. The Thopter does not make up the difference.
• Remote Isle — Enters tapped, and the cycling is the only reason it is here.
• Island — One of 34. Forty lands is one too many once the free artifacts arrive.

Three cards that look like cuts and are not. Graaz, Unstoppable Juggernaut costs eight, but it sets every other creature you control to a base 5/3 — every 1/1 Thopter becomes a 5/3 flier that has to attack, which is the precon's best single finisher and gets better with everything below. Fall from Favor makes you the monarch in the deck best placed to keep it: opponents have to get through a sky of Thopters and pay for Propaganda to take the crown. And Scrawling Crawler hands every opponent a card each upkeep, but charges them a life for every card they draw, from any source — in a long game, that is a clock of its own.

What to add, at three budgets

Every price below is the cheapest English printing in Manamancer's card index on October 23, 2026, leaving out the new Foundations Commander printings and memorabilia. Every card was checked for Commander legality and a blue (or colourless) colour identity, and none of them is on Wizards' Game Changers list — the section on brackets further down says what happens if you add one that is.

Pocket change: under $5 each

Free and nearly free artifacts — the actual fix. Ornithopter ($0.30) costs nothing and flies: with Sai out, that is two fliers for zero mana, and with Archmage out, a card as well. Mishra's Bauble ($1.53) is another free cast that replaces itself at the next upkeep. Chromatic Star ($0.30) costs one and draws a card when it goes to the graveyard — which makes it the best thing in the deck to sacrifice to Sai, since one activation then draws two. Hangarback Walker ($0.26) can be cast for any even amount of mana, and when it dies it leaves a Thopter for every counter on it: the one artifact creature in the list that a board wipe makes more of.

A second Sai. Efficient Construction ($0.51) is Sai's first ability on an enchantment: every artifact spell makes another Thopter. With both out, Ornithopter is three fliers for nothing. Being an enchantment, it also survives the artifact wipes that would take the Thopters with them.

A mana sink that makes threats. Retrofitter Foundry ($0.38) is a one-mana cast that turns spare mana into Servos, Servos into Thopters, and — for no mana, just tapping it — a Thopter into a 4/4 Construct. Its {3} untap lets it do that more than once a turn in the late game, when this deck has mana and nothing to spend it on.

Card advantage that casts artifacts. Mystic Forge ($2.56) lets you cast artifact and colourless spells off the top of your library. Every one of those is a Sai trigger, and in a deck that is nearly half artifacts by card count, it is a second hand.

A win that does not attack. Mechanized Production ($2.10) gets its own section below, because it is the card that changes how this deck closes. Lightning Greaves ($3.49) is shroud and haste for Sai at an equip cost of zero — and, being an artifact, a Sai trigger the turn you cast it. Seat of the Synod ($0.94) replaces Remote Isle: an untapped blue land that is also an artifact, so it counts for affinity, for improvise and for Sai's sacrifice.

Real upgrades: $5 to $20

The four that change the deck most

• Coat of Arms — Every Thopter gets +1/+1 for every other Thopter. $12.27.
• Urza, Lord High Artificer — Every Thopter is a blue mana — the turn it arrives. $15.51.
• Eldrazi Monument — Indestructible fliers, paid for in spare Thopters. $9.24.
• Swan Song — One blue mana to stop the sorcery wipe. $11.02.

Coat of Arms ($12.27) gives each creature +1/+1 for every other creature on the battlefield that shares a type with it. Every Thopter token shares "Thopter" with every other — and so do Ornithopter and Ornithopter of Paradise — so six Thopters are six 6/6 fliers before anything else pumps them. It is symmetrical, so read the table first: against a tribal deck, you are pumping theirs too.

Urza, Lord High Artificer ($15.51) taps any untapped artifact you control for {U}. Because the cost is tapping the artifact rather than the artifact's own tap ability, a Thopter Sai made a moment ago can pay for the next artifact. That is a mana engine running on the same fuel as the card engine, and Urza's Construct token grows with every artifact you have.

Eldrazi Monument ($9.24) gives your creatures +1/+1, flying and indestructible, and asks you to sacrifice a creature each upkeep. In most decks that is a real cost. Here it is one Thopter out of the several Sai made last turn, and in exchange your whole board shrugs off destroy-based wipes and combat.

Swan Song ($11.02) counters an enchantment, instant or sorcery for {U}, and most board wipes are sorceries. The opponent gets a 2/2 bird. You keep the Thopters.

Two more if the budget runs to them. Whir of Invention ($5.52) puts any artifact from your library onto the battlefield at instant speed, and its improvise lets your Thopters help pay — fetch Forsaken Monument or Coat of Arms in the end step before your alpha strike. Unwinding Clock ($19.40) untaps all your artifacts during every other player's untap step, so every rock you tapped on your turn is mana again on theirs — for Shimmer Myr's flash artifacts, for counterspells, and for Shimmer Dragon, which taps two artifacts per card and gets all of them back on every opponent's turn.

For these six slots, the next cuts come from Tamiyo's Logbook, Mazemind Tome, Palladium Myr, Lonely Sandbar, Steel Hellkite and Thopter Fabricator, roughly in that order.

No ceiling

• Urza’s Saga — A land that makes Constructs and fetches a free artifact. $33.39.
• Akroma’s Memorial — Haste for the Thopters you just made. $34.04.
• Darksteel Forge — Every artifact you control, indestructible. $42.85.
• Tezzeret the Seeker — Every artifact a 5/5 for a turn. $25.91.

Urza's Saga ($33.39) takes the place of an Island. Its second chapter makes Constructs that count your artifacts, and its third searches for an artifact with mana cost {0} or {1} and puts it onto the battlefield — after this upgrade, that means Sol Ring, Ornithopter, Mishra's Bauble, Chromatic Star or Retrofitter Foundry, among others. It is the best land in the format for this exact deck.

Akroma's Memorial ($34.04) gives your creatures flying, first strike, vigilance, trample, haste and protection from black and red. The one that matters is haste: the Thopters Sai makes in your main phase can attack the same turn, which takes a full turn cycle off every alpha strike. Vigilance means they still block afterwards.

Darksteel Forge ($42.85) makes every artifact you control indestructible, Thopters included. Destroy-based wipes and artifact removal stop working on your board. It does nothing against exile or bounce, and Sai himself is not an artifact — keep the Greaves on him.

Tezzeret the Seeker ($25.91) enters with four loyalty. Plus one the turn you cast him (untap two rocks, which pays back part of his cost), and on the next turn his −5 turns every artifact you control — Thopters, rocks, Seat of the Synod, Darksteel Citadel — into a 5/5 artifact creature until end of turn. Thopters keep flying. With Forsaken Monument out, they are 7/7s. His −X is also an artifact tutor straight to the battlefield, if the game needs a Coat of Arms more than it needs an alpha strike.

How the deck closes a game

The printed list wins one way: a lot of Thopters, eventually. The upgraded one has three routes, and the point of the package is that they share the same pieces — every one of them is fed by the cheap artifacts that make Sai's Thopters.

1. The air force, made large. The board you are aiming for is Sai, six to eight Thopters and one big anthem. With Forsaken Monument out, six Thopters are six 3/3 fliers — eighteen damage in the air. Add Coat of Arms and each of those Thopters is getting +5 from the other five on top: six 8/8 fliers, forty-eight damage. Or let the precon's own Graaz, Unstoppable Juggernaut set them to a base 5/3, and Monument makes them 7/5s; six of those is forty-two (Graaz drags Sai into every combat as a 5/3 too, so pick the turn). Every route gets there a turn sooner with Akroma's Memorial giving haste to the Thopters made this turn. Whirler Rogue is the answer to the one opponent with flying blockers: tap two artifacts and a creature cannot be blocked.

2. Mechanized Production, which does not attack at all. Enchant a Thopter token. At the beginning of each of your upkeeps, it makes a token copy of that Thopter — and then, if you control eight or more artifacts with the same name, you win the game. Every Thopter token in this deck has the same name, Thopter: Sai's, Efficient Construction's, Thopter Spy Network's, Whirler Rogue's, Hangarback Walker's, Retrofitter Foundry's, Foundry of the Consuls's. So the board that wins is seven Thopter tokens at the start of your upkeep, one of them wearing Production: the copy makes eight, and the game ends before your draw step. Note what does not count — Ornithopter is named Ornithopter, and the Servos are Servos. Thopter Spy Network's own upkeep trigger can be ordered to resolve first, which makes the count one easier. This is the route that ignores Propaganda, fog effects, Ensnaring Bridge and a sky full of blockers. Its weak point is the Aura itself: Padeem, Consul of Innovation gives the enchanted Thopter hexproof, but not Production, which is an enchantment.

3. The drain. Psychosis Crawler makes each opponent lose a life whenever you draw a card, and this deck draws a lot of them. With Vedalken Archmage out, every artifact spell is a Thopter, a card and a life from every opponent; every Sai activation is another. It will rarely kill a table on its own. It is very good at finishing a player the air force left on four.

The ten swaps

If you want one list to take to the shop, it is this one. Prices are the add's cheapest printing on October 23, 2026. The land count drops from 40 to 39, and the deck's artifacts at one mana or less go from three to eight.

Add the four real upgrades above — Coat of Arms, Urza, Eldrazi Monument and Swan Song — for four of the next cuts, and the whole package is $60.41.

What this does to the bracket

The printed list has no Game Changers in our index, and none of the cards recommended above is one either. There are no extra turns, no mass land destruction and no two-card infinite combos, so on paper the upgraded deck is still Bracket 2. Two things are worth saying out loud at the start of a game, though. Mechanized Production wins the game outright, and a table that expects every game to end in combat should hear that before it happens. And Propaganda plus a board of indestructible fliers is a lot to attack through at a Bracket 2 table. As always, a bracket number describes the natural weight class of the shell, not a promise about your list; the stats panel in the builder is where to check yours.

The cards that would move it are the blue staples everyone reaches for first:

• Rhystic Study ($66.76), Cyclonic Rift ($29.53) and The One Ring ($103.49) are all on the Game Changers list in our index, and each is very good here — Rift's overload in particular returns every nonland permanent you do not control, at instant speed. Any one of them puts the deck in Bracket 3, which allows up to three.
• Urza, Lord High Artificer is not flagged as a Game Changer in our index on October 23, 2026, which is why he sits in the middle tier above. Wizards revises that list, so check the current one before you sleeve him.

Open the Keen Engineering decklist — All 100 cards on Manamancer — copy it to your decks and make the swaps.

What to make of it

Keen Engineering's upgrade is cheap for a simple reason: the expensive parts of an artifact deck are the engine and the card draw, and the box already has both. What it leaves out is the cheap stuff — the free artifacts that turn Sai from a card that makes a Thopter now and then into one that makes several a turn — and a way to win that does not depend on the table letting a pile of 1/1s through. Twelve dollars buys most of that. The middle tier makes the fliers large; the top tier makes them hard to kill.

Copy the list from the button above into your decks, make the swaps, and the stats panel will show you the new curve. If you want a second opinion on the last few slots, the Agent tab reviews any Commander deck against deckbuilding quotas and only ever recommends cards that exist — the guide explains how.

May your artifacts always cost less than they look, and may there always be one more Thopter than there are blockers.