Ask Your Journal
A private chat over your own entries: ask why a week felt heavy, when you last slept well, or what triggered last month's slump. Answered on your device by default; nothing goes to a cloud provider unless you turn that on.
Asking a question
Type a question the way you would ask a person: why a particular week felt heavy, when a topic last came up, what tends to precede a good day. Cairn answers from your entries and quotes the ones it used.
It only knows what you told it
There is no outside knowledge here. If you never recorded anything about sleep, no question about sleep will produce an answer — the honest response is that there is nothing to draw on.
Where the answering happens
On-device by default. If you have switched on cloud AI, the entries relevant to your question may be sent for processing; that is the trade you are making for longer answers, and it stays your choice.