/**
 * diagnostics.ts
 *
 * Append-only JSONL diagnostic log at ~/.hmem/diagnostics.log.
 * Rotated to .1 when the file exceeds 1 MB.
 */
export declare function diagnosticsLogPath(): string;
export interface DiagnosticEntry {
    op: string;
    sessionId?: string;
    hmemPath?: string;
    activeProjectId?: string | null;
    oId?: string | null;
    batchId?: string | null;
    markerSource?: "session-marker" | "db-fallback" | "none";
    warning?: string;
    [key: string]: unknown;
}
export declare function writeDiagnostic(entry: DiagnosticEntry): void;