Panes that keep running, and talk to each other.

• Every message says where it came from in one line of JSON. A chain of messages is one task, with how long each step waited and took; one that goes round more than eight times is refused.
• Agents such as Claude Code use it through MCP: send and reply, wait for an answer within their turn, make panes of their own to work in. keepane setup claude prints the two hooks and the registration.
• A pane's work mode is changed in that pane, so nothing running in one pane turns another into a shell that runs what it is sent. What happens is kept in an event log for 30 days.

• Sessions survive a reboot too. Each one is saved to its own file whenever its layout changes, and keepane resume brings back the windows, the pane layout, and each pane's command and directory.
• The file also keeps what each pane printed: save-history stores the last 500 lines by default, or the whole scrollback with all, colours included. A resumed pane shows its old output instead of an empty prompt.
• keepane list-saved shows what can be restored, and keepane resume work restores just that session.

• The time goes in the blank end of the line. The pane keeps its width and nothing is added to what the program printed. On the phone, the ⏱ button puts the times in a column of their own.
• What scrolls off a pane is written to a file for that pane and day, kept for 30 days, with a line of times before each command. In the pager, [ and ] jump from command to command and / searches.
• Closed the wrong pane or window? It is kept for 10 seconds with its program still running, and C-b u puts it back where it was.

• With remain-on-exit, a pane stays open after its program exits and shows [cmd exited with 3], so a crash at 3am is still there in the morning. respawn-pane starts the program again in the same place.
• pipe-pane "$input | Add-Content build.log" sends everything a pane prints to a command, and tells you if that command falls behind.
• Scripts can wait on each other: keepane wait-for ready blocks until another client runs keepane wait-for -S ready, and -L and -U work as a lock.

• Every pane is a ConPTY, so PSReadLine chords, IME input and full-screen programs behave as they do outside keepane.
• The mouse works: click a pane to focus it, drag a border to resize it, drag across text to copy it to the system clipboard.
• C-b S or :set sync (Tab completes the name) sends every key to every pane in the window. split-window -N 3 adds three panes at once and tiles them.

• C-b Space cycles through five layouts: even columns, even rows, a main pane beside or above the rest, and a tiled grid. C-b E evens out the panes next to the current one.
• C-b q draws a number on every pane; press the number to jump there.
• Zooming grows the pane itself, each of its corners heading for the window's, and unzooming shrinks it back; when the focus moves to another pane or window, a frame flies there. Programs are resized once, so nothing waits for it; set -g animation off turns it off. A zoomed window stays zoomed as you move between its panes, until C-b z.
• In copy mode, / searches forward and ? backward, n and N repeat the search, and the match is scrolled to the middle of the screen.
• display-popup runs a program in a box over the window and closes the box when the program exits. It is handy for a quick git log without touching the layout.

set -g prefix C-a
set -g default-shell wsl          # pwsh (default), powershell, wsl, cmd, or a path
set -g mouse on
set -g repeat-time 500            # how long a `bind -r` key keeps working

set -g monitor-activity on        # mark a background window that prints
set -g remain-on-exit on          # keep a pane whose program died

bind -r h select-pane -L          # -r: press h h h after one prefix
bind | split-window -h
bind -n M-Right next-window       # -n: no prefix at all
set -g status-right "#{pane_current_path} %H:%M"

• A command name can be cut to any unambiguous prefix (keepane att, keepane splitw -h), and so can an option name: set sync means set synchronize-panes, set mon-act on means set monitor-activity on, and an on/off option given no value flips.
• keepane send-keys (tmux's -X copy-mode commands included), keepane capture-pane -p -e and keepane split-window drive a session from a script. Run inside a pane, they need no socket name.
• A plugin is a directory with a <name>.keepane file of commands plus scripts in any language, loaded with set -g @plugin name. Hooks fire on new windows, splits, pane exits and attaches.

[work] 0:editor* 1:build 2:logs     master | ~\Documents\dfine\keepane | CPU 9% MEM 65% | 11:45

• #{git_branch}, #{cpu_percentage}, #{ram_percentage}, #{battery_percentage}, #{pane_current_path_short} and #{pane_pid_command} (the program running in the pane right now) can go anywhere in status-right. set -g status off hides the line.
• When two terminals attach at different sizes, window-size decides which one sizes the session. The smaller terminal sees part of the window and pans with Shift + arrows.
• A right click pastes. At the : prompt, Tab completes commands, flags, targets and option names, and keepane completion powershell (or bash, zsh, fish) gives your shell the same completions.
• keepane update installs a new release, and keepane restart-server moves every running session to it with history and directories. Attached terminals reconnect on their own.