/**
 * Rendering message parts as the flat text a human or a model reads.
 *
 * One renderer, so a new core part kind is legible on every surface at once or on none — the
 * copied-out expression it replaces broke on `artifact` in three places the same way, rendering it
 * as an empty string rather than anything a reader could notice.
 *
 * It reaches only the three surfaces that call it (the connector inbox, `cotal join`, the mesh
 * view). Four others still carry their own copy — two stringify, two filter non-text parts out
 * before mapping — and a fix here cannot reach a surface whose defect is that it does not use this.
 */
import type { Part } from "./types.js";
import { type Extension } from "./registry.js";
/**
 * A renderer for ONE extension part kind — an {@link Extension} of kind `"part-renderer"`, whose
 * `name` is the part kind it draws (e.g. `"ag-ui.frame"`).
 *
 * **THIS IS A SEAM, NOT KNOWLEDGE.** Core cannot render an extension's part: it does not know what
 * the payload means, and `AGENTS.md` is explicit that an adapter's concepts must not leak in here.
 * But the alternative that was shipping — every extension part rendering as a marker on every
 * surface — means an extension can put a part on the wire that **nothing in the standard can ever
 * display.** So core declares the contract and stays ignorant of who fills it, exactly as
 * {@link TerminalLayout} does for terminal backends: the provider self-registers on import, and the
 * consumer here resolves by kind without ever importing the extension package.
 *
 * **THE MARKER IS NOT REMOVED, AND THAT MATTERS.** A kind with no registered renderer still renders
 * `[unrenderable part kind …]`. This makes the marker RARER; it does not make absence quiet again.
 */
export interface PartRenderer extends Extension {
    readonly kind: "part-renderer";
    /** The part kind this draws — the `kind` field of the parts it is resolved for. */
    readonly name: string;
    render(part: Part): string;
}
/** A message's parts as one flat string, space-joined. */
export declare function partsToText(parts: readonly Part[]): string;
//# sourceMappingURL=parts.d.ts.map