List all tmux sessions on the current user's tmux server. Returns name, window count, created/activity timestamps (ISO 8601), and attached status. Returns an empty list when no tmux server is running.

Check whether a named tmux session exists. Cheap precondition for capture_pane, send_keys, or kill_session.

List windows within a named session (index, name, active flag, pane count).

Capture the last N lines visible in the session's active pane (default 100, max 10000). Returns the joined text. The primary primitive for "is my training still running? show me the latest output".

Start a new detached tmux session. Always starts a shell (so the session survives after the initial command finishes). If command is given, it is sent to the shell as keystrokes + Enter, so aliases, venvs, and functions work as expected. Errors if the session name already exists.

Send key combos or text to the session's active pane. Use for interrupts (C-c), end-of-input (C-d), or typing a command. Text is sent literally. Enter is appended by default; set enter=false for raw key combos.

Terminate a named tmux session. Any processes running inside are sent SIGHUP by tmux. Errors if the session does not exist.