Prototype Portal — ruling 1

If Prototype Portal has left the battlefield by the time its second ability resolves, you'll still put a token onto the battlefield that's a copy of the exiled card. On the other hand, if Prototype Portal is still on the battlefield at this time but there is no exiled card (because, perhaps, Riftsweeper's ability caused the exiled card to be put into its owner's library), no token is created.

Prototype Portal — ruling 2

You don't choose the value of {X}. Rather, the value of X is defined by the activated ability.

Prototype Portal — ruling 3

If the exiled card has {X} in its mana cost (such as Chalice of the Void), that X is considered to be 0. The {X} in Prototype Portal's activation cost takes this into account, though it may be greater than 0 if the exiled card has other mana symbols in its mana cost (such as Riptide Replicator).

Prototype Portal — ruling 4

You may not activate the second ability if no card has been exiled with Prototype Portal. In that case, the value of {X} is undefined and can't be paid.

Prototype Portal — ruling 5

Any "enters" abilities of the exiled card will trigger when the token is put onto the battlefield. Any "as [this permanent] enters" or "[this permanent] enters with" abilities of the exiled card will also work.

Prototype Portal : règles, fonctionnement et interactions (MTG)

Prototype Portal 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

Imprint — When this artifact enters, you may exile an artifact card from your hand. , : Create a token that's a copy of the exiled card. X is the mana value of that card.

Complete guide

Prototype Portal is a versatile artifact that allows you to manufacture a never-ending supply of your favorite gadgets and gizmos. By imprinting an artifact card from your hand, you turn this portal into a personal factory capable of churning out copies every single turn.

The Imprint Mechanic

When Prototype Portal enters the battlefield, its Imprint ability triggers. You have the choice to exile exactly one artifact card from your hand. This card remains in exile for as long as the Portal is on the battlefield, serving as the blueprint for your future tokens. If you choose not to exile a card, or if the Portal leaves the battlefield before the Imprint trigger resolves, you won't be able to use the second ability.

Building the Copies

The activated ability allows you to create a token that is an exact copy of the exiled card. To do this, you must pay X mana and tap the Portal. The value of X is automatically determined by the mana value of the exiled card; you do not choose this value yourself. If the Portal leaves the battlefield while the ability is on the stack, the ability still resolves using the last known information of the exiled card to create the token.

Mana Values and X Costs

A common point of confusion involves cards with X in their own mana cost. If you exile an artifact with X in its cost, that X is treated as 0 for the purpose of the Portal's activation. Furthermore, since the token created is a copy, it will trigger any 'enters' abilities the original card has, and will function with any 'as this permanent enters' or 'enters with' effects.

Strategic Timing

Because Prototype Portal requires tapping, it is often best played when you have mana available to protect it or use it immediately if you have ways to untap artifacts. Since the activation cost is tied to the mana value of the imprinted card, cheaper artifacts allow for rapid token production, while expensive artifacts provide high-impact value every turn.

Interaction examples

Ramping with the Simulacrum

Solemn Simulacrum

If you exile Solemn Simulacrum with Prototype Portal, the activation cost for the Portal becomes 4 mana. Each time you activate it, you create a Solemn Simulacrum token. Because the token enters the battlefield, its ability triggers, letting you search for a basic land card. When these tokens eventually die, you will also get to draw a card for each.

Continuous Mana and Card Draw

Commander's Sphere

Exiling Commander's Sphere sets the Portal's activation cost to 3. Each turn, you can pay 3 and tap the Portal to create a token copy of the Sphere. This token can immediately be tapped for mana, or sacrificed to draw a card, effectively turning your Portal into a repeatable source of card advantage.

Copying the Copy

Copy

When you activate Prototype Portal, you create a token that is a copy of the exiled card. This process uses a 'Copy' token to represent the new permanent on the battlefield. The token has all the characteristics of the exiled card, including its name, types, and abilities.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Prototype Portal

Original English text — Wizards of the Coast / Scryfall

#1January 1, 2011· Wizards of the Coast
If Prototype Portal has left the battlefield by the time its second ability resolves, you'll still put a token onto the battlefield that's a copy of the exiled card. On the other hand, if Prototype Portal is still on the battlefield at this time but there is no exiled card (because, perhaps, Riftsweeper's ability caused the exiled card to be put into its owner's library), no token is created.
Card named in this ruling
Copy
#2January 1, 2011· Wizards of the Coast
You don't choose the value of . Rather, the value of X is defined by the activated ability.
No other card is named in this ruling.
#3January 1, 2011· Wizards of the Coast
If the exiled card has in its mana cost (such as Chalice of the Void), that X is considered to be 0. The in Prototype Portal's activation cost takes this into account, though it may be greater than 0 if the exiled card has other mana symbols in its mana cost (such as Riptide Replicator).
No other card is named in this ruling.
#4January 1, 2011· Wizards of the Coast
You may not activate the second ability if no card has been exiled with Prototype Portal. In that case, the value of is undefined and can't be paid.
No other card is named in this ruling.
#5January 1, 2011· Wizards of the Coast
Any "enters" abilities of the exiled card will trigger when the token is put onto the battlefield. Any "as [this permanent] enters" or "[this permanent] enters with" abilities of the exiled card will also work.
No other card is named in this ruling.