If a Sefer Torah became self-aware and conscious, would such a Sefer Torah be Halachically allowed to get ink tattooed into it when needed (such as correcting cracked letters)? Or would this constitute getting a tattoo?
The Vilna Gaon says that the klei shares in the mishkan were sentient. He says that this is so because sentience is a function of kedushah, and therefore since the klei shares had the kedushah of the benei yisrael they too were sentient.
(Note: I think I saw this gr"a concerning the klei ha'mishkan but I can't find that reference at the moment.)
Furthermore, see Rashi https://he.wikisource.org/wiki/%D7%99%D7%95%D7%9E%D7%90_%D7%9E%D7%94_%D7%90
ובכלי שרת - בלבוש בגדי כהונה
And we know there was writing on some bigdei kehunah, such as the tzitz. Therefore it is evident that there is no issur of tattooing for a sentient sefer torah.
It may be advisable to consult the sefer torah's therapist beforehand, however.