import type { SpooledArtifact } from "../classes/spooled_artifact";
/**
 * Constructor signature for any {@link @nhtio/adk!SpooledArtifact} (the class itself or a subclass).
 *
 * @remarks
 * Re-declared here at the contract level so consumers — and the `Tool.artifactConstructor`
 * resolver validator in particular — can talk about the constructor shape without value-importing
 * the {@link @nhtio/adk!SpooledArtifact} class (which would close the `tool.ts` ↔ `spooled_artifact.ts` ↔
 * `artifact_tool.ts` module cycle at load time and TDZ-crash `ArtifactTool extends Tool`).
 *
 * @typeParam A - The {@link @nhtio/adk!SpooledArtifact} subtype the constructor produces.
 */
export type SpooledArtifactConstructorLike<A extends SpooledArtifact = SpooledArtifact> = new (...args: any[]) => A;
/**
 * Validator schema used to validate a {@link SpooledArtifactConstructorLike} value.
 *
 * @remarks
 * Because the validator is invoked at validate-time (not at module-load), it is safe to inspect
 * the constructor's prototype here. The check is duck-typed: the value must be a function whose
 * `prototype` carries every canonical artifact instance method (`head`, `tail`, `grep`, `cat`,
 * `byteLength`, `lineCount`, `estimateTokens`). This mirrors {@link spoolReaderSchema}'s
 * cross-realm-safe duck-type pattern — `instanceof SpooledArtifact` would be tighter but would
 * force a value-import of the class and reopen the module cycle.
 */
export declare const spooledArtifactConstructorSchema: import("@nhtio/validation").AnySchema<any>;
/**
 * Returns `true` if `value` is a constructor whose prototype carries every canonical
 * {@link @nhtio/adk!SpooledArtifact} instance method.
 *
 * @remarks
 * Duck-typed; does not use `instanceof SpooledArtifact`. Used by the `Tool.artifactConstructor`
 * resolver validator and any other site that needs to recognise a `SpooledArtifact`-like
 * constructor without pulling the class into its module-load graph.
 *
 * @param value - The value to test.
 * @returns `true` when `value` is a `SpooledArtifact`-shaped constructor.
 */
export declare const implementsSpooledArtifactConstructor: (value: unknown) => value is SpooledArtifactConstructorLike;
/**
 * Creates the validator fragment for a resolver returning a spooled-artifact constructor.
 *
 * The resolver is invoked during validation, then its result is checked with the canonical
 * cross-realm-safe constructor guard. Keeping this fragment here makes `Tool` and `Retrievable`
 * share exactly the same validation behaviour.
 */
export declare const artifactConstructorResolverSchema: () => import("@nhtio/validation").AnySchema<any>;