Due to the threat SCP-XXXX poses to the Institute should it fall into the wrong hands,
This is more or less implicitly assumed about every SCP, so it doesn't need to be added here.
to be kept on a strict need-to-know basis.
Containment procedures are the ultimate rulebook for dealing with an entity. So how is it determined who needs to know? Who approves the dispersal of information?
Initial speculation was raised about SCP-XXXX being a sentient, reading entity,
What does 'reading entity' mean here? Does it mean that it can read other things, or that it exists to be read?
Subjects are able to recall their exact writings in SCP-XXXX indefinitely
I found this a bit confusing, especially the word 'writings'. Do you mean the information recorded, the act of writing, or both?
spilling various substances on SCP-XXXX's pages
'Spilling' implies carelessness. Perhaps 'applying'?
Writing mediums and other on SCP-XXXX's pages vanish completely after SCP-XXXX is closed and opened
I think "writing medium" is an atypical usage here. Writing is itself a medium.
If kept open, SCP-XXXX's contents will not alter, and subjects cannot recall their writings.
So the earlier memory property doesn't work? But if you close it, the writing is erased? So can you only remember erased things?
The term 'hazard' is too vague for this entry, especially as you've already said it's impervious to all 'damage'. You could just say that it is not affected by high temperatures.
subjects able to recall writings with approx. 91.1% accuracy.
This has the same issue as above with the term 'writings'. And does 91.1% accuracy mean after the amnestics are administered?
For this reason, SCP-XXXX is considered a threat to the Foundation as threats to the Foundation could be able to retain classified information after amnestic administration.
I feel like this is an example of on-the-nose writing, where you just spill out the information you want readers to know without fitting it into the story. This is basically a mnestic device (the opposite of amnestics), which are frequently featured in SCP tales and entries. This isn't different enough to be an especially bad threat, and most SCP entries don't explicitly spell out why something is dangerous to the Foundation.
The memory addendum is actualy pretty cool. Some of the early ones seem a bit redundant, though, such as 01, 27, and 30.
For the destruction addendum, it specifically said earlier that the notebook was impervious to damage. Here you're saying that it heals damage, and that's a contradiction.
One typos: "coAver" in the water test.
Destruction addendum is the best thing I've read so far in this document, really good stuff.
A07 and A12 seem pretty redundant in the amnestic logs.
In test A23, the formatting gets messy and difficult to read. Just capitalizing 'log' would help. The trigger phrase idea is also a bit confusing to me.
With the testing of A23, how does the notebook change anything? It seems like the memetic phrase is what's making the recall, and the class-F amnestic is making them forget. Wouldn't a patient without the notebook experience similar confusion?
Subject used food items
You should say that they used them to write with, as they might have been used for consumption or other things.
Why won't you tell me what it is.
Quotation mark at the end.
Due to reports of ████████████ (ETHICS COMMITTEE NOTE: Redaction possibly reads, "compromising") quotes attributed to Dr. Hart etched on the walls of Subject A23's cell, A23 was brought in for questioning.
One of the most realistic uses of redaction I've seen. The bolding in the Ethics Committee Note conflicts with the formatting, though. Maybe using red to represent the ethics committee throughout could help.
