/**
 * Shared output helpers for the hand-authored, server-facing CLI commands.
 *
 * Centralizes color detection (TTY + `NO_COLOR`/`FORCE_COLOR`), human-friendly
 * duration and timestamp rendering, NDJSON serialization, and destructive-action
 * confirmation. Every noun-verb command consumes these helpers so the DX
 * conventions (table on a TTY, NDJSON under `--json`, prompts before destructive
 * operations) stay consistent across the surface.
 *
 * @module cli/output
 */
/** Returns true when ANSI color should be emitted for the given stream. */
export declare function supportsColor(stream?: {
    isTTY?: boolean;
} | undefined): boolean;
/** ANSI color helpers gated by {@link supportsColor}. */
export declare const color: {
    green: (text: string) => string;
    yellow: (text: string) => string;
    red: (text: string) => string;
    cyan: (text: string) => string;
    dim: (text: string) => string;
    bold: (text: string) => string;
};
/**
 * Serialize an array of values as NDJSON: one compact JSON object per line.
 * Entries that `JSON.stringify` cannot encode (e.g. `undefined`, functions)
 * are skipped so the output is always valid NDJSON.
 */
export declare function ndjson(values: readonly unknown[]): string;
/**
 * Pretty-print a single value as indented JSON for non-list `--json` output.
 * Returns `'null'` when `JSON.stringify` yields `undefined` (e.g. for void
 * results) so the contract of returning a valid JSON string is always upheld.
 */
export declare function prettyJson(value: unknown): string;
/** Render a Unix-millisecond timestamp as an ISO string, or `-` when absent. */
export declare function formatTimestamp(value: unknown): string;
/**
 * Render a millisecond duration as a compact human string (e.g. `1.5s`, `2m 3s`,
 * `1h 4m`). Sub-second durations render in milliseconds.
 */
export declare function formatDuration(milliseconds: number): string;
/**
 * Truncate a string to fit a terminal column width, appending an ellipsis when
 * the value is clipped. A non-positive or non-finite width returns the value
 * unchanged so non-TTY output is never lossy.
 */
export declare function truncateToWidth(value: string, width: number): string;
/**
 * Confirmation gate for destructive operations.
 *
 * - `assumeYes` (the `--yes`/`-y` flag) bypasses the prompt entirely and returns `'confirmed'`.
 * - On a non-interactive stdin without `--yes`, returns `'non-interactive'` so the caller
 *   can exit 1 with a clear message rather than hanging on a prompt.
 * - On a TTY, prints `prompt` and reads a line; defaults to No unless the reply
 *   starts with `y`/`Y`. Returns `'confirmed'` or `'denied'` accordingly.
 */
export declare function confirmDestructive(options: {
    readonly prompt: string;
    readonly assumeYes: boolean;
    readonly isTty?: boolean;
    readonly readLine?: () => Promise<string>;
}): Promise<'confirmed' | 'denied' | 'non-interactive'>;
/** Extract a human-readable message from an unknown error value. */
export declare function messageOf(error: unknown): string;