import type { MessagePart } from '../../types/api';
/**
 * Decides, for a single persisted message part, whether the timeline shows its
 * content or an inert placeholder.
 *
 * Every persisted part owns exactly one list row. Some parts have nothing to
 * show *in the timeline* — their content is surfaced by the live status row or
 * the todo panel, or they are simply empty. Those rows used to render `null`,
 * which collapsed them to zero pixels and, worse, flipped a tool call from a
 * full-height box to nothing the moment another part streamed in. This module
 * makes that decision explicit, positional-free and unit testable:
 *
 *  - suppression depends only on the part itself and on whether its tool call
 *    has been resolved, never on the part's index in the turn, so a row's
 *    height changes at most once and only when its own data changes;
 *  - a suppressed part still yields a row, so the part → row mapping stays 1:1
 *    and LegendList keeps a stable, measurable item for it.
 */
export type PartPresentation = 'visible' | 'suppressed';
export interface PartPresentationContext {
    /**
     * Tool call ids in this turn that already have a persisted `tool_result`.
     * A call is interesting only until its result lands.
     */
    resolvedToolCallIds: ReadonlySet<string>;
}
/**
 * Tool results whose content is rendered by the todo panel rather than the
 * thread, so their timeline row has nothing to show.
 */
export declare function isTodoTool(toolName: string | null | undefined): boolean;
/** True when a text/reasoning part carries something worth rendering. */
export declare function hasRenderableText(part: MessagePart): boolean;
/**
 * True when this tool call still renders its live "running…" box. Derived from
 * the call's own result rather than from its position in the turn, so appending
 * unrelated parts can never change it.
 */
export declare function isLiveToolCallPart(part: MessagePart, { resolvedToolCallIds }: PartPresentationContext): boolean;
/**
 * Whether a part renders its content in the timeline. Mirrors exactly the cases
 * `MessagePartItem` declines to render, so moving the decision here changes no
 * visuals — it only replaces a `null` return with a measurable placeholder row.
 */
export declare function getPartPresentation(part: MessagePart, context: PartPresentationContext): PartPresentation;
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