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 sets up the hook and the registration for Claude Code, Codex, Gemini CLI, Cursor CLI or opencode, so the agent is handed its next message when a turn ends; a message for an agent that never says it is free tells you which setup it lacks.
• 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.
• Each agent a pane runs (Claude Code, Codex, pi) shows its model, what it has cost, how full its context is, its tokens, CPU and memory: in the dashboard, on its card on the phone, in keepane list-agents and in #{agent_cost}-style variables. keepane reads the transcripts the agents write; cost is priced by LiteLLM's public list (API list prices), or agent-cost off.

# on the laptop: pair with the desktop, whose keepane web printed this address
keepane link add http://192.168.1.20:7681/#k=...
# a message for the agent pane there
keepane send-message --to 192.168.1.20:7681/%agent "review the diff"
# what that machine runs, and a look at its pane (if it allows it)
keepane link info 192.168.1.20:7681
keepane link capture 192.168.1.20:7681/%agent

• A pane is addressed as host:port/%name or host:port/$1:@3.%7. The answer to a message goes back by pane id, so it still arrives after the pane that asked has been moved.
• Each machine has its own key pair. Pairing uses the other side's phone code once; after that every request and every answer is signed, with the time and a one-off number, so an old one cannot be sent again. A machine is known by its key, not its address.
• What comes from another machine goes to agent and normal panes only. Letting it run as shell commands, read a pane's screen, or start panes here (keepane link start, one of this machine's agent-commands) is allowed per machine with keepane link allow, and only from outside keepane: an agent in a pane cannot grant it to itself.
• Agents get it through MCP too: list_links, link_info, read_screen, and send_message to an address on another machine.

• 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, When each command ran, in the view menu, 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.
• C-b y copies what the last command printed, and nothing else: a failing test's output, ready for an issue or an agent.

• 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.
• Unsure of a key? Press C-b and wait: after half a second a panel says what the keys do, by group, read from your own bindings. The key then works as ever.
• 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.