/**
 * Interactivity predicate — the one source of truth for "can a prompt be
 * answered?" (tty-prompt-guard/AC-1).
 *
 * This lives in `core/` rather than `menu/` even though `menu/prompt.ts`
 * authored the predicate: `menu/index.ts` imports the command registrars in
 * order to dispatch, so a command reaching into `menu/` for one function would
 * close an import cycle. Every prompt site in the package — `commands/`,
 * `doctor/`, `menu/` — reads it from here.
 *
 * @module
 */
/**
 * Both streams must be a TTY (interactive-cli-menu/AC-10, tty-prompt-guard/AC-1).
 *
 * clack reads keys from stdin and renders to stdout, so either alone is
 * insufficient: `aidlc | less` has a TTY stdin with a piped stdout and would
 * paint escape sequences into the pipe, while `echo x | aidlc` has the reverse
 * and would render a prompt nobody can answer. Both idioms exist in this
 * package (`commands/cost.ts` keys on stdin; `doctor/context.ts` keyed on stdout
 * until tty-prompt-guard/AC-11), so the conjunction is stated explicitly rather
 * than inherited from a precedent.
 *
 * Deliberately *not* environment sniffing (`CI`, `TERM`, `FORCE_COLOR`): two
 * `isTTY` reads are deterministic, so a runner and a laptop cannot disagree
 * about whether a prompt was openable.
 */
export declare function isInteractive(): boolean;
/**
 * Shared reason clause for a prompt that cannot be opened
 * (tty-prompt-guard/AC-14).
 *
 * Seven call sites explain the same condition. One constant keeps them from
 * drifting apart and gives the regression tests a single string to assert on
 * instead of seven hand-copied sentences.
 */
export declare const NO_TTY_REASON = "no interactive terminal (stdin and stdout must both be a TTY)";
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