import type { ValidationDefect } from "./contract.js";
/**
 * Which part of the import failed. One shape for every host, whatever stage raised it
 * (FR-56): a discovery failure, a blocked plan and a landing failure are all this.
 */
export type ImportStage = "target" | "discovery" | "plan" | "preview" | "blocked" | "confirmation" | "source-changed" | "landing";
export interface ImportFailureDetail {
    defects?: ValidationDefect[];
    cause?: unknown;
}
/**
 * What every operation of the pipeline rejects with. It is an `Error` so a host that only
 * prints the throwable still shows what failed and what to do next (FR-56).
 */
export declare class ImportFailure extends Error {
    readonly stage: ImportStage;
    /** The structural defects, when a target adapter refused the new session (FR-50). */
    readonly defects: ValidationDefect[];
    constructor(stage: ImportStage, message: string, detail?: ImportFailureDetail);
}
/** The first line of whatever a stage threw. Never the raw throwable (FR-56). */
export declare function reasonOf(cause: unknown): string;