export declare const FLEET_DEVELOPER_INSTRUCTIONS_SUFFIX: string;
export declare function isFleetModeEnabled(value?: string | undefined): boolean;
export declare function appendFleetDeveloperInstructions(developerInstructions: string | null | undefined): string | undefined;
/**
 * Build the full developerInstructions string for a thread/start call.
 * Composes: user instructions → question guidance → fleet sentinel.
 */
export declare function buildDeveloperInstructions(userInstructions: string | undefined, provider: string): string | undefined;