import type { RuntimeHost } from '../host.js';
export interface LocalFileSystemAccessEvent {
    op: 'read' | 'write';
    /** Resolved absolute path on disk. */
    path: string;
    /** Path relative to the sandbox root. */
    relativePath: string;
}
export interface LocalFileSystemHostOptions {
    /** Absolute path to the sandbox root. All accesses must resolve under this directory. */
    root: string;
    /**
     * Called after each successful IO. Use this to wire your own logging/audit;
     * the helper itself does not log. Errors thrown here propagate to the caller.
     */
    onAccess?: (event: LocalFileSystemAccessEvent) => void;
    /**
     * If true, allow paths whose realpath escapes `root` via symlinks. Defaults
     * to `false` — symlinked-out paths are rejected the same way as `..` escapes.
     */
    followSymlinksOutsideRoot?: boolean;
}
export type LocalFileSystemHost = Required<Pick<RuntimeHost, 'readTextFile' | 'writeTextFile'>>;
/**
 * Build a `RuntimeHost` partial that implements ACP `fs/read_text_file` and
 * `fs/write_text_file` against the local filesystem, sandboxed to a single
 * `root` directory.
 *
 * Compose with your own permission/terminal handlers:
 *
 * ```ts
 * const fsHost = createLocalFileSystemHost({ root: workingDirectory });
 * const runtime = createAcpRuntime({
 *   profile,
 *   host: { ...fsHost, requestPermission: myPrompt },
 * });
 * ```
 *
 * Security model:
 * - `root` must be an absolute path; relative roots are rejected.
 * - Every requested path is resolved against `root`, then `realpath`-checked
 *   to ensure it still lives under `root`. `..` traversal and (by default)
 *   symlinks pointing outside the sandbox throw before any IO happens.
 *
 * Not appropriate when:
 * - Your host serves multiple workspace roots (e.g. a VS Code multi-root window) —
 *   write a host that picks the right root per request instead.
 * - The agent runs on a different machine than the files (use a transport
 *   that proxies `fs/*` to the real client).
 */
export declare function createLocalFileSystemHost(options: LocalFileSystemHostOptions): LocalFileSystemHost;