To summarise in case this has been done before its essentially a magic keyboard that spawns things into reality if it has already been made please reference the SCP number so I can make changes
I don't think there's a magic stuff-spawning keyboard on the site, probably because it's not a great concept to begin with. It's honestly a fairly-common trope, often for funny reasons—Smosh did a youtube video involving a magic keyboard back in 2012: https://www.youtube.com/watch?v=XJ87Lsx40PI and the cartoon series Johnny Test did something similar with a video game controller.
the keyboard can create anything real the user wants be it living, dead, an object even another SCP however it will only have the features/ability's the user believes
due to its end of the world ability's it would only be accessible with permission of a level 4 personnel (<- or only level 5 not to sure)
This makes it way, way too powerful, and SCP objects that are too outwardly possible without there being much reason for it or story behind it tend to tank on the mainsite.
I think this should be classed as Thaumiel as with some clever manipulation of class D personal objects capable of containing SCPs could be created
I disagree. I think it'd be Safe class since it's easy to contain. I'm not too sure about Thaumiel because it doesn't really seem geared towards containment, just spawning random stuff. That said, Thaumiel class articles tend to be among the most scrutinized on the mainsite, so if you're really invested in writing a Thaumiel, be prepared to put a lot of extra time and effort into the writing process.
To be honest, I can't see this working. It's pretty much the definition of the wish-granter trope, and we've seen plenty of similar attempts at this sort of thing get wiped from the site because they're predictable and come off as kind of shallow due to how straightforwardly and obviously overpowered they are.
I rarely say this, but I recommend trying another idea.