open-design/packages/contracts/src/sse/chat.ts

import type { SseErrorPayload } from '../errors';
import type { SseTransportEvent } from './common';

export const CHAT_SSE_PROTOCOL_VERSION = 1;

export interface ChatSseStartPayload {
  runId?: string;
  agentId?: string;
  bin: string;
  protocolVersion?: typeof CHAT_SSE_PROTOCOL_VERSION;
  /** Legacy daemon-internal absolute cwd. Kept for compatibility during W2 adoption. */
  cwd?: string | null;
  projectId?: string | null;
  model?: string | null;
  reasoning?: string | null;
}

export interface ChatSseChunkPayload {
  chunk: string;
}

export interface ChatSseEndPayload {
  code: number | null;
  signal?: string | null;
  status?: 'succeeded' | 'failed' | 'canceled';
}

export type DaemonAgentPayload =
  | { type: 'status'; label: string; model?: string; ttftMs?: number; detail?: string }
  | { type: 'text_delta'; delta: string }
  | { type: 'thinking_delta'; delta: string }
  | { type: 'thinking_start' }
  | { type: 'tool_use'; id: string; name: string; input: unknown }
  | { type: 'tool_result'; toolUseId: string; content: string; isError?: boolean }
  | { type: 'usage'; usage?: { input_tokens?: number; output_tokens?: number }; costUsd?: number; durationMs?: number }
  | { type: 'raw'; line: string };

export type ChatSseEvent =
  | SseTransportEvent<'start', ChatSseStartPayload>
  | SseTransportEvent<'agent', DaemonAgentPayload>
  | SseTransportEvent<'stdout', ChatSseChunkPayload>
  | SseTransportEvent<'stderr', ChatSseChunkPayload>
  | SseTransportEvent<'error', SseErrorPayload>
  | SseTransportEvent<'end', ChatSseEndPayload>;