import type { UIMessagePart, UIDataTypes, UITools } from "ai";
/** Tool-set-agnostic: only `type` and a few fields are read. */
export type AgentUIPart = UIMessagePart<UIDataTypes, UITools>;
/**
 * Folded from ai's 7-state tool machine. `awaiting` is a call parked on a human decision, distinct
 * from `running` so the feed never pulses it.
 */
export type AgentStepStatus = "running" | "awaiting" | "done" | "error";
/** `toolName` is raw; the renderer maps it (`resolveToolMeta`). */
export interface AgentStep {
    id: string;
    toolName: string;
    status: AgentStepStatus;
    /**
     * Read from the `approval` record, since the state forgets at settle. An `isAutomatic` approval
     * is the system's, not an operator's.
     */
    decided: boolean;
    /** Revealed on demand, never inline. */
    input?: unknown;
    output?: unknown;
    errorText?: string;
}
export type AgentSegment = {
    kind: "text";
    id: string;
    text: string;
} | {
    kind: "reasoning";
    id: string;
    text: string;
} | {
    kind: "group";
    id: string;
    steps: AgentStep[];
};
/**
 * Consecutive tool parts collapse into one group; prose gets a synthesized index id. Kinds with no
 * feed representation are skipped, as chat's renderer skips them.
 */
export declare function toSegments(parts: readonly AgentUIPart[]): AgentSegment[];
export declare function anyRunning(segments: readonly AgentSegment[]): boolean;
export declare function lastRunningStep(segments: readonly AgentSegment[]): AgentStep | undefined;
/**
 * The split is positional: a model emits plan, aside and report all as `text`, so what follows the
 * last tool call is the answer and everything before it is the work.
 */
export interface AgentTimeline {
    process: AgentSegment[];
    /** Empty when the run stopped on a tool call — exactly when the work must not fold away. */
    result: AgentSegment[];
    /** Flattened, for a run-level summary. */
    steps: AgentStep[];
}
/** Pure: fresh arrays, nothing mutated. */
export declare function splitTimeline(segments: readonly AgentSegment[]): AgentTimeline;