Before I go I have to get this off of my chest as it has been bugging me since day 1.
Now the SCP foundation contains loads of weird unexplained phenomenon that in our current understanding of things makes no sense whatsoever.
If so HOW THE BLOODY HELL CAN THERE BE CANON!!!?
There I said it.
All the things ive seen shot down on SCP forums because they are not "canon"
ITS A CREEPYPASTA ABOUT A FOUNDATION SHOVING THINGS THAT DONT MAKE SENSE UNDER A RUG!!!
Its kind of a sick metaphore in this own sense WHY!!?
Sorry but this thread had to be made! It has haunted me since the first day I heard about the foundation!

Not sure what your issue with this is.
Any SCP that gets accepted on the "Official SCP-Wiki" counts as cannon, no matter what strange characteristics they have.
So if anyone posts whatever they can come up with it'll naturally be refused. Why?
Because the SCPs that are used need to be KNOWN BY MORE THAN ONE PERSON. So why the thread? It's not difficult to understand.

So why is the Bible canon? It's just a book a bunch of people wrote and released.
Same thing in a way. The Community as a whole decides on cannon SCPs not the single User.

-edit-

Wait, you posted about you LEAVING 30mins before creating THIS thread? What's the point since you're "leaving" and therefore not being able to read answers?

I just had to know before I leave.

Actually, if you read the wiki on how to write an SCP, it says there is actually no cannon. You could write whatever you wanted about an SCP on a tale or another SCP and if people like it, then it will be accepted, whether it goes against the main article or not.

Although there is technically no cannon, what is said on the SCP documents is taken as cannon.