fix(realtime-ws): stop accidental cancellation error (#220)

Author: dkundel-openai

.changeset/strong-lobsters-repair.md

@@ -0,0 +1,6 @@
+---
+"@openai/agents-extensions": patch
+"@openai/agents-realtime": patch
+---
+
+fix(realtime-ws): stop accidental cancellation error

packages/agents-extensions/src/TwilioRealtimeTransport.ts

@@ -181,7 +181,7 @@ export class TwilioRealtimeTransportLayer extends OpenAIRealtimeWebSocket {
     super.updateSessionConfig(newConfig);
   }
 
-  _interrupt(_elapsedTime: number) {
+  _interrupt(_elapsedTime: number, cancelOngoingResponse: boolean = true) {
     const elapsedTime = this.#lastPlayedChunkCount + 50; /* 50ms buffer */
     this.#logger.debug(
       `Interruption detected, clearing Twilio audio and truncating OpenAI audio after ${elapsedTime}ms`,
@@ -192,7 +192,7 @@ export class TwilioRealtimeTransportLayer extends OpenAIRealtimeWebSocket {
         streamSid: this.#streamSid,
       }),
     );
-    super._interrupt(elapsedTime);
+    super._interrupt(elapsedTime, cancelOngoingResponse);
   }
 
   protected _onAudio(audioEvent: TransportLayerAudio) {

packages/agents-extensions/test/TwilioRealtimeTransport.test.ts

@@ -91,7 +91,7 @@ describe('TwilioRealtimeTransportLayer', () => {
       toString: () => JSON.stringify({ event: 'mark', mark: { name: 'u:5' } }),
     });
     transport._interrupt(0);
-    expect(interruptSpy).toHaveBeenCalledWith(55);
+    expect(interruptSpy).toHaveBeenCalledWith(55, true);
     expect(twilio.send).toHaveBeenCalledWith(
       JSON.stringify({ event: 'clear', streamSid: 'sid' }),
     );

packages/agents-extensions/test/index.test.ts

@@ -64,7 +64,10 @@ describe('TwilioRealtimeTransportLayer', () => {
     const payload = { event: 'mark', mark: { name: 'badmark' } };
     twilio.emit('message', { toString: () => JSON.stringify(payload) });
 
-    transport._interrupt(0);
+    transport._interrupt(0, false);
+    // @ts-expect-error - we're testing protected fields
+    transport._audioLengthMs = 500;
+    transport._interrupt(0, true);
 
     const call = sendEventSpy.mock.calls.find(
       (c) => c[0]?.type === 'conversation.item.truncate',

packages/agents-realtime/src/openaiRealtimeBase.ts

@@ -104,6 +104,7 @@ export abstract class OpenAIRealtimeBase
   #model: string;
   #apiKey: ApiKey | undefined;
   #tracingConfig: RealtimeTracingConfig | null = null;
+  #rawSessionConfig: Record<string, any> | null = null;
 
   protected eventEmitter: RuntimeEventEmitter<OpenAIRealtimeEventTypes> =
     new RuntimeEventEmitter<OpenAIRealtimeEventTypes>();
@@ -149,6 +150,10 @@ export abstract class OpenAIRealtimeBase
 
   abstract readonly muted: boolean | null;
 
+  protected get _rawSessionConfig(): Record<string, any> | null {
+    return this.#rawSessionConfig ?? null;
+  }
+
   protected async _getApiKey(options: RealtimeTransportLayerConnectOptions) {
     const apiKey = options.apiKey ?? this.#apiKey;
 
@@ -186,6 +191,10 @@ export abstract class OpenAIRealtimeBase
       return;
     }
 
+    if (parsed.type === 'session.updated') {
+      this.#rawSessionConfig = parsed.session;
+    }
+
     if (parsed.type === 'response.done') {
       const response = responseDoneEventSchema.safeParse(parsed);
       if (!response.success) {

packages/agents-realtime/src/openaiRealtimeWebsocket.ts

@@ -215,7 +215,15 @@ export class OpenAIRealtimeWebSocket
 
         const buff = base64ToArrayBuffer(parsed.delta);
         // calculate the audio length in milliseconds assuming 24kHz pcm16le
-        this._audioLengthMs += buff.byteLength / 24 / 2; // 24kHz * 2 bytes per sample
+        const audioFormat =
+          this._rawSessionConfig?.output_audio_format ?? 'pcm16';
+        if (audioFormat.startsWith('g711_')) {
+          // 8kHz * 1 byte per sample
+          this._audioLengthMs += buff.byteLength / 8;
+        } else {
+          // 24kHz * 2 bytes per sample
+          this._audioLengthMs += buff.byteLength / 24 / 2;
+        }
 
         const audioEvent: TransportLayerAudio = {
           type: 'audio',
@@ -224,7 +232,9 @@ export class OpenAIRealtimeWebSocket
         };
         this._onAudio(audioEvent);
       } else if (parsed.type === 'input_audio_buffer.speech_started') {
-        this.interrupt();
+        const automaticResponseCancellationEnabled =
+          this._rawSessionConfig?.turn_detection?.interrupt_response ?? false;
+        this.interrupt(!automaticResponseCancellationEnabled);
       } else if (parsed.type === 'response.created') {
         this.#ongoingResponse = true;
       } else if (parsed.type === 'response.done') {
@@ -343,8 +353,16 @@ export class OpenAIRealtimeWebSocket
    *
    * @param elapsedTime - The elapsed time since the response started.
    */
-  _interrupt(elapsedTime: number) {
+  _interrupt(elapsedTime: number, cancelOngoingResponse: boolean = true) {
+    if (elapsedTime < 0 || elapsedTime > this._audioLengthMs) {
+      return;
+    }
+
     // immediately emit this event so the client can stop playing audio
+    if (cancelOngoingResponse) {
+      this._cancelResponse();
+    }
+
     this.emit('audio_interrupted');
     this.sendEvent({
       type: 'conversation.item.truncate',
@@ -362,16 +380,15 @@ export class OpenAIRealtimeWebSocket
    * You can also call this method directly if you want to interrupt the conversation for example
    * based on an event in the client.
    */
-  interrupt() {
+  interrupt(cancelOngoingResponse: boolean = true) {
     if (!this.#currentItemId || typeof this._firstAudioTimestamp !== 'number') {
       return;
     }
 
-    this._cancelResponse();
-
     const elapsedTime = Date.now() - this._firstAudioTimestamp;
-    if (elapsedTime >= 0 && elapsedTime < this._audioLengthMs) {
-      this._interrupt(elapsedTime);
+
+    if (elapsedTime >= 0) {
+      this._interrupt(elapsedTime, cancelOngoingResponse);
     }
 
     this.#currentItemId = undefined;