/**
 * StreamAssembler — stateful utility for reassembling fragmented agent output.
 *
 * Operates in two modes:
 * - Line mode (default): each line is returned as-is from feed().
 * - Block mode: lines are accumulated until a termination condition is met.
 *
 * @see 05-adapter-system.md §6
 */
/** Predicate that determines when a block is complete. */
export type BlockTerminator = (line: string, accumulated: string) => boolean;
/**
 * Stateful utility for reassembling fragmented agent output into
 * complete, parseable units. One instance per run.
 */
export declare class StreamAssembler {
    private _buffer;
    private _terminator;
    /**
     * Feeds a line into the assembler. In line mode, returns the line
     * unchanged. In block mode, accumulates the line and returns null
     * until the block is complete, then returns the assembled block.
     */
    feed(line: string): string | null;
    /**
     * Begins block accumulation mode. Subsequent calls to feed()
     * will accumulate lines until endBlock() is called or the
     * termination predicate returns true.
     */
    startBlock(terminator: BlockTerminator): void;
    /**
     * Forces the current block to end and returns whatever has been
     * accumulated so far. Returns null if not in block mode.
     */
    endBlock(): string | null;
    /** Whether the assembler is currently in block accumulation mode. */
    get inBlock(): boolean;
    /**
     * Resets the assembler to its initial state.
     */
    reset(): void;
    /**
     * Returns the number of lines currently accumulated in the buffer.
     * Zero when not in block mode.
     */
    get bufferedLineCount(): number;
    /**
     * Returns the raw accumulated content without ending the block.
     */
    peek(): string;
}