export interface TmuxInstall {
    cmd: string;
    args: string[];
    /** Linux package managers need root; brew must NOT run as root. */
    needsRoot: boolean;
}
/**
 * Pure: the package-manager command to install tmux on this platform, given
 * which manager binaries exist (`has`). null when none is available or the
 * platform isn't covered — the caller then stays on node-pty.
 */
export declare function tmuxInstallCommand(platform: NodeJS.Platform, has: (bin: string) => boolean): TmuxInstall | null;
export interface EnsureTmuxDeps {
    /** Find tmux now (resolveBin("tmux")). Called again after an install. */
    resolve: () => string | null;
    /** The install command for this host, or null (tmuxInstallCommand(...)). */
    plan: () => TmuxInstall | null;
    /** Run the install command. */
    install: (c: TmuxInstall) => Promise<void>;
    /** Progress / fallback guidance. */
    notify: (line: string) => void;
}
export interface EnsureTmuxResult {
    /** tmux got installed by us this run. */
    installed: boolean;
    /** tmux is available now (already there, or installed). */
    present: boolean;
    note?: "no-manager" | "install-failed";
}
/**
 * Best-effort: make tmux available so agents survive a server restart (with
 * node-pty they die on every auto-update). NEVER blocks — if tmux can't be
 * installed (no package manager, or it needs a password we don't have) we say
 * so and stay on node-pty. Pure orchestration over injected deps, so it is
 * tested without touching the system.
 */
export declare function ensureTmux(deps: EnsureTmuxDeps): Promise<EnsureTmuxResult>;