import type { HostFiles } from "../../host/host.js";
import type { Checkpoint } from "../state/checkpointStore.js";
import { type TraceSink } from "./sinks.js";
import type { TraceConfig } from "./types.js";
/**
 * Decide which file (if any) a trace writer should target for a given run.
 *
 * - `traceFile` set: use it verbatim. This is a fixed, process-wide path —
 *   useful for tests and single-run inspection, but NOT safe with concurrent
 *   runs of the same agent (they'd interleave into one file). Documented.
 * - `traceFile` unset, `traceDir` set: derive `${traceDir}/${runId}.agencytrace`.
 *   Each run gets its own file, naturally supporting concurrent runs without
 *   any shared state.
 * - Neither set: returns null (no file output; callback-only or disabled).
 */
export declare function resolveTraceFilePath(traceConfig: TraceConfig, runId: string): string | null;
export declare class TraceWriter {
    private store;
    private sinks;
    private checkpointCount;
    private chunkCount;
    private program;
    private runId;
    private headerWritten;
    constructor(runId: string, program: string, sinks: TraceSink[], options?: {
        seenHashes?: Set<string>;
        headerWritten?: boolean;
    });
    writeHeader(): Promise<void>;
    writeStaticState(values: Record<string, unknown>): Promise<void>;
    writeCheckpoint(checkpoint: Checkpoint): Promise<void>;
    /** Flush and close all sinks without emitting a footer.
     *  Used when execution is pausing for an interrupt. */
    pause(): Promise<void>;
    /** Emit a footer and close all sinks.
     *  Used when the agent run is truly finished. */
    close(): Promise<void>;
    private writeLine;
    /** `files` is the file part of the run's host, which the trace file is
     *  written through. A host without `fileWrite` refuses the open here,
     *  while the context is built. */
    static create({ runId, traceConfig, files, }: {
        runId: string;
        traceConfig: TraceConfig;
        files: HostFiles;
    }): Promise<TraceWriter | null>;
}