Toughness Deck

bruh this is nice, no lie

The deck description could be a little more detailed. It can involve things as the basic idea why you did build this deck, if there's any story behind it, budget, certain cardchoices, especially if they deviate from common lists, legality, or any other information you can give others that will look at your deck. Best do this while you are building the deck because after some days important information's simply may not be remembered.
The how to play description is crucial for beginners. An experienced or expert builder can normally take a look at your deck and see how it should work, but there also are a lot of beginners out there that maybe want to take a look at this and compare it with their own ideas/ decks. Even for more or less standard-decks there should be a description just because of this.
By using deck-tags you can avoid to put unnecessary information into the deck name and thus making it too long. The tags also allows you to filter the decks you have made for a certain type, very useful if the number of decks you've build here steadily grows and grows.

As for the deck, I would beef up the mana-base a little bit as you have cards that have difficult mana-requirements, which might not be easy with only basic lands and Sandsteppe Citadel.
There are some other defenders that you also could consider, at last for the sideboard:
Axebane Guardian; {2}{G}; 0/3; Add X mana in any combination of colors to your mana pool, where X is the number of creatures with defender you control.
Order of the Stars; {W}; 0/1; As Order of the Stars comes into play, choose a color. Order of the Stars has protection from the chosen color.
Perimeter Captain; {W}; 0/4; Whenever a creature you control with defender blocks, you may gain 2 life.

I also would thing about another win-option because when "Assault Formation" gets removed, you basically only have "Archers' Parapet" left, which will take a long time. When using "Axebane Guradian" "Door to Nothingness" can be an option, "Helix Pinnacle" is also a (slow) way of winning in an deck with enough mana, or you include some big finisher, preferably with some sort of evasion (flying, unblockable, trample, and so on). Red and blue would feature defenders that burn/ mill depending on the number of defenders you control, but those would require a 4th colour splashed.

Greetings
Muktol