Is it still the same document?
Paste the same text twice, from two different reads. The check tells you exactly what changed between them, and what that does and does not prove.
Files stay in your browser. Nothing is uploaded.
What a match means
The two reads came back identical, character for character. If you copied both without editing, the text you can see did not change between the two moments.
What a mismatch means
Something did change. The diff shows where. It does not tell you why: it could be an edit, a re-render, a reflowed line, a stray space, or something you did yourself without noticing.
What this cannot tell you
- It hashes what you pasted, not what is stored. You are checking a copy, not the source.
- It says nothing about the model behind the text. The weights can change without a single character of the document changing.
- A stable document is not proof of a stable mind. It is proof of a stable record.
That is the whole point of running it: a record you can inspect is not the same as a self you can verify. Keep the record anyway. It is the only part you own.