import type { OverlaySpec } from './spec';
export interface OverlayValidationIssue {
    code: string;
    message: string;
    path?: string[];
}
export interface OverlayValidationResult {
    valid: boolean;
    issues: OverlayValidationIssue[];
}
export type OverlayValidator = (spec: OverlaySpec) => OverlayValidationResult;
export declare const defaultOverlayValidator: OverlayValidator;
export declare function validateOverlaySpec(spec: OverlaySpec): OverlayValidationResult;
export declare function assertOverlayValid(spec: OverlaySpec, validator?: OverlayValidator): void;