First time only, a small AI model (~25 MB, all-MiniLM-L6-v2) downloads from a CDN and is cached in your browser. After that it works offline. Your documents are never uploaded.
Meaning search finds passages by concept — it works even when the document uses different words than you do.
Pulls the most central real sentences from the document — nothing is invented.
Changing passage size or overlap requires rebuilding the index.