/**
 * Newline-delimited JSON message framing - the exact wire format
 * @modelcontextprotocol/sdk uses for stdio (see its own ReadBuffer in
 * dist/esm/shared/stdio.js: messages are `JSON.stringify(message) + '\n'`,
 * split on the first '\n', with a trailing '\r' tolerated on read).
 *
 * Buffers as raw bytes (not strings) so a multi-byte UTF-8 character split
 * across two chunks is never corrupted.
 */
export declare class NdjsonReader {
    private buffer;
    /** Feed a raw chunk of bytes read from a stream. */
    push(chunk: Buffer): void;
    /**
     * Pull the next complete line, if any, as a raw string (not yet parsed).
     * Returns undefined if no complete line is buffered yet.
     */
    readLine(): string | undefined;
    /** Drain and return every complete line currently buffered, in order. */
    readAllLines(): string[];
}
/** JSON-RPC 2.0 message shape, classified structurally (no schema validation). */
export type ParsedMessage = {
    kind: 'request';
    id: string | number;
    method: string;
    raw: unknown;
} | {
    kind: 'notification';
    method: string;
    raw: unknown;
} | {
    kind: 'response';
    id: string | number;
    raw: unknown;
} | {
    kind: 'unparseable';
    raw: string;
};
/**
 * Classify a raw NDJSON line. Never throws - an unparseable or
 * unrecognizable line is still forwarded (as 'unparseable'), since the
 * supervisor's job is to proxy, not to police the protocol.
 */
export declare function classifyLine(line: string): ParsedMessage;
export declare function serializeMessage(message: unknown): string;
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