---
type: email
from: Shehan Panditharatne <notifications@github.com>
subject: [openai/openai-agents-python] error: cannot update a conversation's

 voice if assistant audio is present bug (Issue #1661)
received: 2026-03-06 07:21:44
date_header: Thu, 04 Sep 2025 08:29:35 -0700
priority: normal
status: awaiting_approval
uid: 29512
---

## Email Content

**From:** Shehan Panditharatne <notifications@github.com>
**Subject:** [openai/openai-agents-python] error: cannot update a conversation's

 voice if assistant audio is present bug (Issue #1661)
**Date:** Thu, 04 Sep 2025 08:29:35 -0700

### Body (preview)

shehan360 created an issue (openai/openai-agents-python#1661)



### Describe the bug

Started receiving the following error message through the realtime session recently,



```

Error(message="Cannot update a conversation's voice if assistant audio is present.", type='invalid_request_error', code='cannot_update_voice', event_id=None, param=None)

```



This only seems to happens if you have a model_config passed to runner.run() method.



### Debug information

- Agents SDK version: 0.2.10

- Python version: Python 3.10



### Repro steps



1. Setup the `examples/realtime/app/server.py`

2. Change the runner.run() line (https://github.com/openai/openai-agents-python/blob/6df6fe16ee3ebb4daa5d70ecfab78903b555b184/examples/realtime/app/server.py#L46) to the following

```

        session_context = await runner.run(

            model_config=RealtimeModelConfig(

                initial_model_settings=RealtimeSessionModelSettings(

                    model_name="gpt-4o-realtime-preview-2025-06-03",

                    input_audio_format="pcm16",

                    output_audio_format="pcm16",

                    input_audio_transcription=RealtimeInputAudioTranscriptionConfig(

                        model="gpt-4o-transcribe",

                        language="en",

                    ),

                    voice="alloy",

                    speed=1.2,

                ),

            )

        )

```

3. Talk to the agent and get past the handover. 

4. Right after the handover you should see

```

Error(message="Cannot update a conversation's voice if assistant audio is present.", type='invalid_request_error', code='cannot_update_voice', event_id=None, param=None)

```





### Expected behavior

A clear and concise description of what you expected to happen.





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