/**
 * Backend factory.
 *
 * `'claude'` is wired to `ClaudeBackend` (a thin adapter over the existing
 * `agent/src/claude.ts` driver). Copilot and Codex currently use their
 * process drivers directly through runtime.ts rather than this AgentBackend
 * factory.
 */
import { type BackendType, type AgentBackend, type StartOpts } from './types.js';
export * from './types.js';
export { ClaudeBackend } from './claude.js';
export declare class UnknownBackendError extends Error {
    constructor(type: string);
}
export declare class BackendNotImplementedError extends Error {
    constructor(type: BackendType);
}
/**
 * Validate that a string is a known BackendType.
 * Throws UnknownBackendError for unknown values.
 */
export declare function assertKnownBackendType(type: string): asserts type is BackendType;
/**
 * Factory entry point. For recognized-but-not-yet-implemented backends
 * (currently: copilot and codex in this abstraction layer), throws
 * BackendNotImplementedError. Throws UnknownBackendError for unknown types.
 */
export declare function createBackend(type: string, _opts?: StartOpts): AgentBackend;