Containment Breach — ruling 1

If Containment Breach resolves, and the target artifact has a mana value of 2 or less, but it wasn't destroyed (perhaps because it has indestructible), you will still create a Pest.

Containment Breach — ruling 2

If the artifact or enchantment is an illegal target as Containment Breach tries to resolve, it won't resolve and none of its effects will happen. You won't create a Pest.

Containment Breach — ruling 3

Lesson is a spell subtype found on some instant and sorcery cards in the Strixhaven set. The Lesson subtype has no special rules associated with it.

Containment Breach — ruling 4

Although you may want to include Lessons in your sideboard if you're playing with cards that instruct you to learn, Lesson cards can be included in your main deck like other instant or sorcery cards.

Containment Breach : règles, fonctionnement et interactions (MTG)

Containment Breach 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

Destroy target artifact or enchantment. If its mana value is 2 or less, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."

How it works : Containment Breach

Original English text — Wizards of the Coast / Scryfall

#1April 16, 2021· Wizards of the Coast
If Containment Breach resolves, and the target artifact has a mana value of 2 or less, but it wasn't destroyed (perhaps because it has indestructible), you will still create a Pest.
Card named in this ruling
Pest
#2April 16, 2021· Wizards of the Coast
If the artifact or enchantment is an illegal target as Containment Breach tries to resolve, it won't resolve and none of its effects will happen. You won't create a Pest.
Card named in this ruling
Pest
#3April 16, 2021· Wizards of the Coast
Lesson is a spell subtype found on some instant and sorcery cards in the Strixhaven set. The Lesson subtype has no special rules associated with it.
No other card is named in this ruling.
#4April 16, 2021· Wizards of the Coast
Although you may want to include Lessons in your sideboard if you're playing with cards that instruct you to learn, Lesson cards can be included in your main deck like other instant or sorcery cards.
No other card is named in this ruling.