/** Sanitized, whitespace-collapsed, length-capped tail of command output. */
export declare function tailOf(value: string | undefined): string;
/**
 * Coerce an unknown thrown value to its message string. Prefer this over the
 * inline `error instanceof Error ? error.message : String(error)` so error
 * stringification stays uniform. Note: this does NOT redact -- sites that emit
 * to public-bound artifacts must run the result through `redactText` first.
 */
export declare function toErrorMessage(error: unknown): string;
/**
 * True when `error` is (structurally) the @e2b/desktop CommandExitError: a
 * non-zero substrate command exit that the real Sandbox surfaces as a THROW.
 * Matches either the SDK class name (`name === "CommandExitError"`) or any object
 * carrying a numeric `exitCode` (the same field `commandFailureInfo` reads, so a
 * structural fake is covered without importing the SDK class).
 *
 * Deliberately conservative — it is the RECOVERABILITY predicate the CUA loop uses
 * to skip a single failed desktop action instead of ending the whole run: it must
 * NOT match a deadline/abort control-flow signal (those subclass Error without a
 * name override or an exitCode) or a generic Error with no exit signal, so only a
 * genuine substrate-command failure is treated as recoverable.
 */
export declare function isCommandExitError(error: unknown): boolean;
/**
 * Recover the exit code + a sanitized stderr/stdout tail from a command failure.
 * The real @e2b/desktop CommandExitError exposes exitCode/stderr/stdout/error;
 * these are read structurally so the caller does not depend on the SDK class.
 */
export declare function commandFailureInfo(error: unknown): {
    exitCode?: number;
    stderrTail: string;
};
/**
 * Run a desktop command; if the substrate THROWS on a non-zero exit (the real
 * @e2b/desktop behavior), convert the throw into the caller's intended error via
 * `onFailure` (which returns the value to throw -- a new Error, or the original
 * error to preserve raw propagation). A non-throwing runner that RETURNS a
 * non-zero exitCode is left to the caller's own post-call check.
 */
export declare function runDesktopCommandOrThrow<T>(run: () => Promise<T>, onFailure: (info: {
    exitCode?: number;
    stderrTail: string;
}, error: unknown) => unknown): Promise<T>;