/**
 * headlines.ts, per-node headlines + the stall tell for the fleet read-model.
 *
 * OWNER'S LINE (the contract this module enforces): a headline that updates
 * when an agent moves to a new task is fine; a headline that constantly
 * streams new text is not. So:
 *
 *   - A node's headline is DERIVED from its task/phase identity only, never
 *     from tool chatter, output lines, or an agent's per-turn progress text.
 *     Same identity ⇒ the byte-identical headline object (same `updatedAt`),
 *     replaced in place on a transition. There is no API through which a
 *     caller can push arbitrary headline text, so no surface can turn the
 *     field into a feed.
 *   - The length cap is enforced HERE, at the read-model, not per surface.
 *
 * The stall tell is pure timestamp comparison: a live node whose last
 * observed activity is older than the threshold gains a quiet marker
 * (`since`, `quietForMs`), no generated text, ever.
 */
import type { ProcessHeadline, ProcessNode, ProcessStallTell } from './types.js';
/** Read-model cap on headline text, enforced here so every surface inherits it. */
export declare const HEADLINE_MAX_CHARS = 80;
/** Default stall-tell threshold: a live node quiet this long gains the marker. */
export declare const DEFAULT_STALL_TELL_MS: number;
/**
 * The task/phase identity a node's headline derives from, the ONLY input
 * that can change a headline. Agent nodes deliberately exclude their `phase`
 * activity (the orchestrator's per-turn `Turn N · Tool` progress line churns
 * every tool call, a feed, not a transition); orchestration/workflow nodes
 * include their phase activity text because it changes exactly at phase
 * transitions.
 */
export declare function headlineSource(node: ProcessNode): string | null;
/**
 * Registry-owned headline side-table. `derive` returns the EXISTING headline
 * object (byte-stable, same `updatedAt`) while the node's task/phase identity
 * is unchanged, and regenerates, replacing in place, only on a transition.
 */
export declare class HeadlineTable {
    private readonly entries;
    derive(node: ProcessNode, now: number): ProcessHeadline | undefined;
    /** Drop entries for nodes no longer present so the table cannot leak. */
    prune(liveNodeIds: ReadonlySet<string>): void;
}
/**
 * Pure timestamp comparison: a live node whose last observed activity
 * (`currentActivity.at`, falling back to `startedAt`) is at least
 * `thresholdMs` old gains the quiet marker. No text is generated, surfaces
 * render the marker however they like.
 */
export declare function deriveStallTell(node: ProcessNode, now: number, thresholdMs: number): ProcessStallTell | undefined;
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