/** Does THIS process sit inside a tmux client (its own $TMUX is set)? NOT the
 *  gate for the human surface — see tmuxServerReachable. A headless-broker child
 *  strips TMUX/TMUX_PANE (broker.ts, anti-stophook-hijack) yet can still drive
 *  the canvas tmux server, so gating the surface on this wrongly starves broker
 *  nodes of human-in-the-loop. */
export declare function isInTmux(): boolean;
/** Is the canvas tmux SERVER reachable? The canvas runs on the DEFAULT tmux
 *  socket (no -L/-S in core/runtime/tmux.ts), so any `crtr` child — including a
 *  headless-broker child that has deleted its own $TMUX — can split panes into
 *  it. The human surface gates on THIS (can I reach the server to open a pane
 *  the user is watching?), not on the caller's $TMUX. `list-clients` exits 0
 *  whenever a server is up (even with zero attached clients) and non-zero when
 *  no server is running — the true "no tmux to surface into" case that should
 *  degrade to the inbox-drain follow-up. */
export declare function tmuxServerReachable(): boolean;
export declare function shellQuote(s: string): string;