Sweep the Skies — ruling 1

You can choose any value for X. Choosing a higher value for X lets you pay more mana and thus spend more colors of mana to cast it. For example, if you choose 0 for the value of X and pay {U}{U} to cast Sweep the Skies, you'll create one Thopter. If you choose 4 for the value of X and pay {W}{U}{U}{B}{R}{G}, you'll create five Thopters.

Sweep the Skies — ruling 2

The maximum number of colors of mana you can spend to cast a spell is five. Colorless is not a color. Note that the cost of a spell with converge may limit how many colors of mana you can spend.

Sweep the Skies — ruling 3

Unless a spell or ability allows you to, you can't choose to pay more mana for a spell with a converge ability just to spend more colors of mana. Likewise, if a spell or ability reduces the amount of mana it costs you to cast a spell with converge, you can't ignore that cost reduction in order to spend more colors of mana.

Sweep the Skies — ruling 4

If there are any alternative or additional costs to cast a spell with a converge ability, the colors of mana spent to pay those costs will count.

Sweep the Skies — ruling 5

If you cast a spell with converge without spending any mana to cast it (perhaps because an effect allowed you to cast it without paying its mana cost), then the number of colors spent to cast it will be zero.

Sweep the Skies — ruling 6

If a spell with a converge ability is copied, no mana was spent to cast the copy, so the number of colors of mana spent to cast the spell will be zero. The number of colors spent to cast the original spell is not copied.

Sweep the Skies : règles, fonctionnement et interactions (MTG)

Sweep the Skies is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Converge — Create a 1/1 colorless Thopter artifact creature token with flying for each color of mana spent to cast this spell.

How it works : Sweep the Skies

Original English text — Wizards of the Coast / Scryfall

#1June 18, 2021· Wizards of the Coast
You can choose any value for X. Choosing a higher value for X lets you pay more mana and thus spend more colors of mana to cast it. For example, if you choose 0 for the value of X and pay to cast Sweep the Skies, you'll create one Thopter. If you choose 4 for the value of X and pay , you'll create five Thopters.
Card named in this ruling
Thopter
#2June 18, 2021· Wizards of the Coast
The maximum number of colors of mana you can spend to cast a spell is five. Colorless is not a color. Note that the cost of a spell with converge may limit how many colors of mana you can spend.
No other card is named in this ruling.
#3June 18, 2021· Wizards of the Coast
Unless a spell or ability allows you to, you can't choose to pay more mana for a spell with a converge ability just to spend more colors of mana. Likewise, if a spell or ability reduces the amount of mana it costs you to cast a spell with converge, you can't ignore that cost reduction in order to spend more colors of mana.
No other card is named in this ruling.
#4June 18, 2021· Wizards of the Coast
If there are any alternative or additional costs to cast a spell with a converge ability, the colors of mana spent to pay those costs will count.
No other card is named in this ruling.
#5June 18, 2021· Wizards of the Coast
If you cast a spell with converge without spending any mana to cast it (perhaps because an effect allowed you to cast it without paying its mana cost), then the number of colors spent to cast it will be zero.
No other card is named in this ruling.
#6June 18, 2021· Wizards of the Coast
If a spell with a converge ability is copied, no mana was spent to cast the copy, so the number of colors of mana spent to cast the spell will be zero. The number of colors spent to cast the original spell is not copied.
No other card is named in this ruling.