Ask your matter's documents

Upload a matter's PDFs. Every answer cites the page it came from, says what was not read, and refuses when the documents do not say.

Matter by matter. Colleagues see a matter only when its owner adds them — the firm admin included.
Ethical walls. Screen a lawyer from a matter; they cannot be added back until the screen is lifted, and both acts are logged.
Your key. Each firm's documents are encrypted under its own key, read only through credentials scoped to one matter.