export interface TuiCapability {
    ok: boolean;
    reason?: string;
}
export interface TuiEnv {
    stdoutIsTTY: boolean | undefined;
    stdinIsTTY: boolean | undefined;
    columns: number | undefined;
    rows: number | undefined;
}
export declare const MIN_COLS = 60;
export declare const MIN_ROWS = 14;
/**
 * Decide whether the full-screen TUI can run in the current terminal.
 * Pure and env-injected so it can be unit-tested without a real TTY.
 * Requires both stdio ends to be TTYs and a minimum window size; otherwise
 * the caller falls back to the classic REPL.
 */
export declare function evaluateTui(env: TuiEnv): TuiCapability;
export declare function canUseTui(): TuiCapability;