OpenAI Realtime Conversation

Implements the OpenAI Realtime API for voice conversation with audio streaming.

/**
 * OpenAI Realtime Conversation Provider
 *
 * Full conversation mode: Twilio audio -> OpenAI Realtime (STT + LLM + TTS) -> mu-law -> Twilio.
 *
 * Uses the GA Realtime API (the beta API shape was retired by OpenAI with
 * error code `beta_api_shape_disabled`). Event handlers accept both GA and
 * legacy beta event names for safety.
 */

import WebSocket from "ws";

export interface RealtimeConversationConfig {
  apiKey: string;
  model?: string;
  voice?: string;
  systemPrompt?: string;
  silenceDurationMs?: number;
  vadThreshold?: number;
  turnDetection?: "server_vad" | "semantic_vad";
  vadEagerness?: "low" | "medium" | "high" | "auto";
  language?: string;
  tools?: RealtimeToolDefinition[];
}

/** Function tool exposed to the realtime model during a call. */
export interface Re

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