Thread read state

Monad remembers three related things separately: how far the thread's natural unread frontier has advanced, which individual messages were actually rendered for you, and whether you want the thread to stay on your radar.

Opening a thread acknowledges only the replies that were present when the thread opened. If a new reply arrives a moment later, it remains new. A future catch-up recap can use the exact messages that were rendered—not merely a bulk “mark all read” frontier—while leaving newer replies visible below it.

Choose Mark unread in the thread header when you want to come back later. This adds a reminder marker; it does not pretend that you never saw the messages or erase your reading history. Choose Clear unread marker when you no longer need the reminder. The control stays disabled with Unread state loading… until the thread's saved state is ready, so a tap can never look successful while being silently ignored.

Channels have the same Mark all as read / Mark unread controls in their own header menu — see Spaces → Spaces overview.