Chat Branching AI Block for Radix UI

Everything. Four typed questions have three versions each, and anything else answers with one. Nothing is sent and no model runs, as the line under the composer says. To wire it for real, send the message in post, store each version your model returns on the exchange (count and at say how many exist and which one is shown) and call it again from regen for the next one.

A branch is a list of exchanges. Forking copies the exchanges before the one you edited, adds the edited message with its own answer, and keeps the old list untouched, so switching back shows the original thread with every version. A forked message says "Edited, forked" under it. The demo allows three branches and says so when you reach the limit.

Previous and next move through the versions of that one answer without replaying them, and each says "Version 2 of 3" in the polite status line. At either end the button stays focusable and says "This is the first version" or "This is the newest version" instead of doing nothing. While a version is arriving the pager is hidden but keeps its room, so nothing moves.

The Branch button opens a small popover with one radio per branch, named by the message that forked it. Arrow keys move between radios, a pointer press picks and closes, and the thread changes at once. Switching is held back while an answer is arriving, with a line that says so.

The log is a focusable region announced as a log. Edit is a button named "Edit your message", the edit field has a hidden label, Enter forks and Escape cancels with focus back on Edit. Previous and next have names, and one polite line says what changed.

The same single column. The Branch button keeps its place in the top bar, the pager and actions stay in one row under each answer, and the edit field takes the full width of the log. The window keeps its height and only the log scrolls.