/**
 * Shared client metadata validators
 *
 * Used by both DCR (dcr.ts) and CIMD (cimd.ts) so both registration paths
 * enforce identical rules. Keep dcr.ts behavior identical when importing
 * from here.
 */
export declare const SUPPORTED_GRANT_TYPES: Set<string>;
export declare const SUPPORTED_RESPONSE_TYPES: Set<string>;
/** Auth methods supported for DCR clients. CIMD clients in v1 are restricted to 'none'. */
export declare const SUPPORTED_AUTH_METHODS: Set<string>;
export declare const LOCAL_HOSTS: Set<string>;
export declare function validateOptionalString(value: unknown, fieldName: string): string | null;
/**
 * Validate a single redirect URI against RFC 7591 + RFC 8252 rules.
 * Returns an error message on failure, null on success.
 */
export declare function validateRedirectUri(uri: unknown, allowedHosts: string[] | undefined): string | null;
export declare function validateStringArray(value: unknown, fieldName: string): string | null;
export declare function validateGrantTypes(grantTypes: string[]): string | null;
export declare function validateResponseTypes(responseTypes: string[]): string | null;
export declare function validateAuthMethod(method: string): string | null;