import type { DocumentNode } from 'graphql';
import { ValidationMessage } from '../../../model/validation/message.js';
import type { ASTValidator } from '../ast-validator.js';
export declare const VALIDATION_ERROR_INVALID_OBJECT_TYPE = "A @key field can only be declared on root entities.";
export declare class KeyFieldValidator implements ASTValidator {
    validate(ast: DocumentNode): ReadonlyArray<ValidationMessage>;
}