tmux Skill (Otto)

Use tmux only when you need an interactive TTY. Prefer exec background mode for long-running, non-interactive tasks.

Quickstart (isolated socket, exec tool)

SOCKET_DIR="${OTTO_TMUX_SOCKET_DIR:-${TMPDIR:-/tmp}/otto-tmux-sockets}"
mkdir -p "$SOCKET_DIR"
SOCKET="$SOCKET_DIR/otto.sock"
SESSION=otto-python

tmux -S "$SOCKET" new -d -s "$SESSION" -n shell
tmux -S "$SOCKET" send-keys -t "$SESSION":0.0 -- 'PYTHON_BASIC_REPL=1 python3 -q' Enter
tmux -S "$SOCKET" capture-pane -p -J -t "$SESSION":0.0 -S -200

After starting a session, always print monitor commands:

To monitor:
  tmux -S "$SOCKET" attach -t "$SESSION"
  tmux -S "$SOCKET" capture-pane -p -J -t "$SESSION":0.0 -S -200

Socket convention

• Use

  OTTO_TMUX_SOCKET_DIR

  .
• Default socket path:

  "$OTTO_TMUX_SOCKET_DIR/otto.sock"

  .

Targeting panes and naming

• Target format:

  session:window.pane

  (defaults to

  :0.0

  ).
• Keep names short; avoid spaces.
• Inspect:

  tmux -S "$SOCKET" list-sessions

  ,

  tmux -S "$SOCKET" list-panes -a

  .

Finding sessions

• List sessions on your socket:

  {baseDir}/scripts/find-sessions.sh -S "$SOCKET"

  .
• Scan all sockets:

  {baseDir}/scripts/find-sessions.sh --all

  (uses

  OTTO_TMUX_SOCKET_DIR

  ).

Sending input safely

• Prefer literal sends:

  tmux -S "$SOCKET" send-keys -t target -l -- "$cmd"

  .
• Control keys:

  tmux -S "$SOCKET" send-keys -t target C-c

  .
• For interactive TUI apps like Claude Code/Codex, this guidance covers how to send commands. Do not append

  Enter

  in the same

  send-keys

  . These apps may treat a fast text+Enter sequence as paste/multi-line input and not submit; this is timing-dependent. Send text and

  Enter

  as separate commands with a small delay (tune per environment; increase if needed, or use

  sleep 1

  if sub-second sleeps aren't supported):

tmux -S "$SOCKET" send-keys -t target -l -- "$cmd" && sleep 0.1 && tmux -S "$SOCKET" send-keys -t target Enter

Watching output

• Capture recent history:

  tmux -S "$SOCKET" capture-pane -p -J -t target -S -200

  .
• Wait for prompts:

  {baseDir}/scripts/wait-for-text.sh -t session:0.0 -p 'pattern'

  .
• Attaching is OK; detach with

  Ctrl+b d

  .

Spawning processes

• For python REPLs, set

  PYTHON_BASIC_REPL=1

  (non-basic REPL breaks send-keys flows).

Windows / WSL

• tmux is supported on macOS/Linux. On Windows, use WSL and install tmux inside WSL.
• This skill is gated to

  darwin

  /

  linux

  and requires

  tmux

  on PATH.

Orchestrating Coding Agents (Codex, Claude Code)

tmux excels at running multiple coding agents in parallel:

SOCKET="${TMPDIR:-/tmp}/codex-army.sock"

# Create multiple sessions
for i in 1 2 3 4 5; do
  tmux -S "$SOCKET" new-session -d -s "agent-$i"
done

# Launch agents in different workdirs
tmux -S "$SOCKET" send-keys -t agent-1 "cd /tmp/project1 && codex --yolo 'Fix bug X'" Enter
tmux -S "$SOCKET" send-keys -t agent-2 "cd /tmp/project2 && codex --yolo 'Fix bug Y'" Enter

# When sending prompts to Claude Code/Codex TUI, split text + Enter with a delay
tmux -S "$SOCKET" send-keys -t agent-1 -l -- "Please make a small edit to README.md." && sleep 0.1 && tmux -S "$SOCKET" send-keys -t agent-1 Enter

# Poll for completion (check if prompt returned)
for sess in agent-1 agent-2; do
  if tmux -S "$SOCKET" capture-pane -p -t "$sess" -S -3 | grep -q "❯"; then
    echo "$sess: DONE"
  else
    echo "$sess: Running..."
  fi
done

# Get full output from completed session
tmux -S "$SOCKET" capture-pane -p -t agent-1 -S -500

Tips:

• Use separate git worktrees for parallel fixes (no branch conflicts)

• pnpm install

  first before running codex in fresh clones
• Check for shell prompt (

  ❯

  or

  $

  ) to detect completion
• Codex needs

  --yolo

  or

  --full-auto

  for non-interactive fixes

Cleanup

• Kill a session:

  tmux -S "$SOCKET" kill-session -t "$SESSION"

  .
• Kill all sessions on a socket:

  tmux -S "$SOCKET" list-sessions -F '#{session_name}' | xargs -r -n1 tmux -S "$SOCKET" kill-session -t

  .
• Remove everything on the private socket:

  tmux -S "$SOCKET" kill-server

  .

Helper: wait-for-text.sh

{baseDir}/scripts/wait-for-text.sh

polls a pane for a regex (or fixed string) with a timeout.

{baseDir}/scripts/wait-for-text.sh -t session:0.0 -p 'pattern' [-F] [-T 20] [-i 0.5] [-l 2000]

• -t

  /

  --target

  pane target (required)

• -p

  /

  --pattern

  regex to match (required); add

  -F

  for fixed string

• -T

  timeout seconds (integer, default 15)

• -i

  poll interval seconds (default 0.5)

• -l

  history lines to search (integer, default 1000)