This article suffers from very rough clinical tone and improper organization/introduction of elements, which makes for a confusing read the first time through; a reader is forced to read the article twice before really getting what is going on. The gradual introduction of the elements that make up the final picture (adoration for the cosmos, encouragement and beauty, etc) could serve as some sort of "arc," but the organization detracts from this possibility.
Furthermore, at certain points there is a significant discrepancy between what the article is attempting to accomplish and what it is, especially in the section about its own music — the absence of any examples make for an uncomfortably aware read where the limitations of the author are brought to mind too often.
The poetic exploration of the beauty in the universe is rather weirdly secondary to the musical aspect. It gives the impression that the article is intended to be about 655's personality, or some sort of arc of personality that is implied but not followed upon. The short length of the overall product significantly harms this implied development as well — there is not enough time to experience it. This could be fixed if the article was written with a progression like that of SCP-3001 in mind, perhaps with shorter messages to mankind/Authority/itself rather than extensive hopeless monologues about nothingness.
The ending addendum is also rather weird. It introduces this neat empathic aspect to 655's personality that is nice, just abruptly attached and disconnected from the rest of the article. If it were formatted like a series of logs, it would make for a beautiful intermission (perhaps with less RPC links and more references to one-off personnel?) + character expansion. Could also be accentuated by having the Authority remain largely hostile toward 655 (in the sense of continuing to attempt containment or neutralization) despite its friendly behavior.
This also reminds me of RPC-983 in a good way, although I think 983 is significantly more successful.
Overall; beautiful concept squandered in execution. +2