import type { PiIntegrationTestRuntimeArtifacts } from "./artifacts.js";
import type { PiIntegrationTestState, TraceEvent } from "../scenario/types.js";
export interface SessionSnapshot {
    readonly messages: readonly unknown[];
    readonly state: PiIntegrationTestState | undefined;
}
export declare function readTrace(file: string, allowPartialLine?: boolean): Promise<TraceEvent[]>;
export declare function waitForSettledTrace(tracePath: string, expectedProviderRequestCount: number, timeoutMs: number): Promise<void>;
/** Wait for the settlement event belonging to a real user-provider agent run. */
export declare function waitForAgentSettledTrace(tracePath: string, timeoutMs: number): Promise<void>;
/**
 * Reads a growing JSONL trace incrementally.
 *
 * Each poll reads only the bytes appended since the previous one and parses every complete line
 * once, so waiting on a large trace costs time proportional to the new events, not the whole file.
 * A line without its trailing newline stays pending until a later poll completes it.
 */
export declare class TraceTail {
    private readonly file;
    private readonly events;
    private offset;
    private pending;
    constructor(file: string);
    /** Return every complete event written so far. */
    poll(): Promise<readonly TraceEvent[]>;
    private consume;
}
export declare function getSessionSnapshot(traceEvents: readonly TraceEvent[]): SessionSnapshot | undefined;
export declare function copySessionFileFromTrace(runtime: PiIntegrationTestRuntimeArtifacts, tracePath: string): Promise<void>;
export declare function waitForNonEmptyFile(filePath: string, timeoutMs: number): Promise<void>;
export declare function delay(milliseconds: number): Promise<void>;