import type { ArtifactRef, ArtifactValue } from "./types.js";
/**
 * Value externalization for run bundles (see docs/run-bundles.md): string
 * leaves larger than the threshold are written once, content-addressed, under
 * `artifacts/` and replaced by `{ "$artifact": ref }`. Because artifacts are
 * immutable and deduplicated by hash, the same output appearing in `outputs`,
 * `results`, `steps`, and the trace costs one file plus small references.
 */
export declare const ARTIFACT_THRESHOLD_BYTES = 4096;
export declare const ARTIFACTS_DIR = "artifacts";
export declare function isArtifactValue(value: unknown): value is ArtifactValue;
/**
 * Writes externalized string leaves for one run bundle. Instances serialize
 * their writes and deduplicate by content hash, so encoding the same large
 * string in several value positions touches the filesystem once.
 */
export declare class ArtifactWriter {
    private readonly runDir;
    private readonly written;
    private chain;
    private dirCreated;
    constructor(runDir: string);
    /** True once any artifact exists for this run. */
    get hasArtifacts(): boolean;
    externalize(text: string): Promise<ArtifactValue>;
}
/**
 * Encode a persisted value: externalize large string leaves and escape
 * single-key `$artifact`/`$escaped` objects so the sentinel stays
 * unambiguous. Returns the original value when nothing changed.
 */
export declare function encodeValue(value: unknown, writer: ArtifactWriter, thresholdBytes?: number): Promise<unknown>;
/**
 * Walk a persisted value, replacing every `$artifact` sentinel via `resolve`
 * and unwrapping `$escaped` objects. `resolve` may return the artifact
 * contents or a placeholder; it receives the reference untouched.
 */
export declare function decodeValueWith(value: unknown, resolve: (ref: ArtifactRef) => unknown): unknown;
/** Resolve every artifact reference in `value` by reading the bundle files. */
export declare function resolveArtifacts(value: unknown, runDir: string): Promise<unknown>;