export interface CodexHistoryEntry {
    session_id?: unknown;
    ts?: unknown;
    text?: unknown;
}
export interface CodexHistorySummary {
    promptCount: number;
    sessionCount: number;
    lastPromptAtMs: number;
}
export declare function computeExternalAgentBuildId(label: string, version: string): string;
export declare function resolveCodexHome(): string;
export declare function resolveCodexHistoryFile(): string;
export declare function isCodexControlPrompt(value: unknown): boolean;
export declare function summarizeCodexHistoryJsonl(text: string): CodexHistorySummary;
export declare function loadCodexHistorySummary(historyFile?: string): CodexHistorySummary | null;