/**
 * Artifact Store
 *
 * Pluggable storage for externalized MCP tool outputs.
 *
 * When `mcp.outputLimits.strategy = "externalize"` the full tool payload is
 * written here instead of being sent inline to the LLM. The model receives a
 * compact surrogate with a preview and an artifact ID. The full payload can be
 * retrieved on demand via the `retrieve_context` tool.
 *
 * Architecture:
 *   ArtifactStore (interface) — canonical types in src/lib/types/artifactTypes.ts
 *   LocalTempArtifactStore   — single-process, filesystem-backed implementation
 *
 * Distributed backends (S3, Redis blobs) can be added later by implementing
 * ArtifactStore from types/artifactTypes.ts.
 *
 * @module artifacts/artifactStore
 */
import type { ArtifactMeta, ArtifactRef, ArtifactStore } from "../types/index.js";
/**
 * Filesystem-backed artifact store using the OS temp directory.
 *
 * Files are written with mode 0o600 (owner read/write only).
 * An in-memory index tracks metadata without a separate index file.
 *
 * Suitable for:
 *  - CLI usage
 *  - Single-process SDK deployments
 *  - Multi-process deployments where each process manages its own artifacts
 *    (artifacts created in one process are not visible to others)
 *
 * @example
 * ```typescript
 * const store = new LocalTempArtifactStore();
 * const ref = await store.store(largeJson, {
 *   toolName: "list_files",
 *   serverId: "filesystem-server",
 *   sizeBytes: Buffer.byteLength(largeJson),
 *   contentType: "json",
 * });
 * // Later, via retrieve_context:
 * const full = await store.retrieve(ref.id);
 * ```
 */
export declare class LocalTempArtifactStore implements ArtifactStore {
    private readonly dir;
    private readonly index;
    constructor(dir?: string);
    generatePreview(payload: string): string;
    store(payload: string, meta: Omit<ArtifactMeta, "createdAt">): Promise<ArtifactRef>;
    retrieve(id: string): Promise<string | null>;
    delete(id: string): Promise<void>;
    cleanup(olderThanMs: number): Promise<number>;
}