/**
 * Thrown when code invokes an optional sandbox capability that the active
 * provider does not support. Core/middleware should check
 * `handle.capabilities` BEFORE using an optional capability and degrade
 * gracefully; this error exists so that a direct call to an unsupported
 * optional method fails loud instead of silently no-opping.
 */
export declare class UnsupportedCapabilityError extends Error {
    readonly provider: string;
    readonly capability: string;
    constructor(provider: string, capability: string, hint?: string);
}
/** Thrown when a harness adapter requires a sandbox but none was provided. */
export declare class MissingSandboxError extends Error {
    constructor(adapterName: string);
}