Cache Keepalive
After this many seconds without activity on the active connection profile, the current chat plus this message (sent as a hidden user message) is submitted to that profile to keep its server-side prompt cache warm. The completion is capped to a single token and is never saved to the chat. Sending is briefly locked while it runs. Only the profile you're currently using is pinged; each profile has its own idle timer. Keepalive stays off until you send a new message in the current chat (opening, switching to, or reloading a chat isn't proof its prompt is still cached), and it also skips a ping if its timer fired far later than scheduled (e.g. after the machine slept).
Turn keepalive on only for the profiles whose providers support prompt caching (leave the others off so you don't waste requests). The master switch above must be enabled. Profiles default to on.