The object is clearly sentient though sapience has proven difficult to determine
Comma after "sentient".
Despite being constructed of entirely of mechanical and computational components
Remove the first "of".
The satellite receiver appears to act as SCP-XXXX's method of sight and is directly linked with SCP-XXXX's discharge hereby referred to as SCP-XXXX-1.
Comma after "discharge".
SCP-XXXX-1 is a powerful beam of EIWO1 light that extends to distances between 60 m and 150 m before collapsing on itself.
The footnote here is a bit long. You might be able to get away with just explaning the acronym and moving on, especially since you say "before collapsing on itself".
It emanates and is discharged via the computer monitor at an 87 degree angle to object's right track.
May want to elaborate a bit here when you say "object's right track".
This discharge seems involuntary but may be linked to SCP-XXXX's emotional state.
This sentence seems unnecessary. I think it'd be more effective implied than explicit like this.
SCP-XXXX has two modes which display on the computer monitor located behind the receiver.
State the two modes here to introduce them to the reader. It works better than saying "The second mode displayed is "PL@Y"." in the middle of the paragraph.
No instance of SCP-XXXX-1 has been documented while in this mode, even when metallic sheet is removed.
"the" before "metallic".
All tests and interactions are to be set up during "R3ST" and conducted during "PL@Y".
This is a containment procedure, as it pertains to when testing is most useful to be conducted.
This is when all previously mentioned behaviors have been recorded.
This would best worded differently. "All notable activity from SCP-XXXX has occurred while the "PL@Y" mode was engaged."
The foundation
The Foundation is the name of an organization, making it a proper noun, meaning it should be capitalized.
So this recovery log doesn't tell us much more than we have already gotten from the description. The reiteration here isn't doing wonders. Also, what did they expect? It's a laser beam and they know it can burn through things easily, so why would the approach it so carelessly?
I recommend removing the recovery log, or at least summarizing it. It doesn't seem to really do much more than what is already relayed in the description.
Interview was conducted by [REDACTED] with [REDACTED] (father of Billy, maker of SCP-XXXX).
How does the Foundation know that this is the creator? When did they detain him?
Not much, unfortunately. My boy made him (starts to break down and begins sobbing)
Seems a bit suddenly dramatic. If you've ever spoken with someone dealing with the grief of loss, they are typically well-composed, especially if its been a few days since the loss. That's not to say you can't have them break down, but you want to give it a little more time and a little more than mentioning the deceased.
Researcher: What about that saying?
Father: Oh that. (chuckles) That was their game.
This makes no sense to me. What do you mean by "saying"?
While the interview provides some origin backing, there needs to be some stuff to support it. All of the sudden we have this father and this boy, but not once have they come up in the article until now. I'm a bit unsure of the interview's place in the article. I could see it fitting in (maybe with some reworking of the father's composure here), but you'll want to be wary not to detract much from the primary focus of the article.
Similar feelings about the addendum here. Not sure if it has a place in this article. It's brief enough that I'm willing to overlook it. Ideally though, there should be a better illustration of what "progress" is here. I'm not sure what they are working towards in terms of a goal.
The entirety of Addendum XXXX.400R is pointless. I'll be transparent here and say that I did not read the footnotes, because I'm not going to subject myself to a wall of legal text. To read it all and then have the Ethics Committee bend to the opposition anyway chalks up to a waste of time. I see no use for having this communique.