export type RuntimeCommandOptions = {
    /** Injected by tests; defaults to the real user home. */
    home?: string;
    json?: boolean;
};
/**
 * `jam runtime` - inspect or change which JAM build this machine runs.
 *
 * The config module is imported from the launcher rather than reimplemented
 * here: the launcher reads this file on every MCP start, so a second writer
 * with its own idea of the format is how the two drift apart.
 *
 * This command touches ~/.jam/config.yaml only. It never writes to a project.
 */
export declare function showRuntime(options?: RuntimeCommandOptions): number;
export declare function useRuntime(mode: string | undefined, source: string | undefined, options?: RuntimeCommandOptions): number;