session.updateHistory doesn't support audio turns

[josephtannenbaum]

Please read this first

• Have you read the docs? Agents SDK docs Yes
• Have you searched for related issues? Others may have faced similar issues. Yes

Describe the bug

I'm trying to store a realtime conversation while it's in progress, and restore it later. When I access session.history, I get RealtimeItems that look like this:

[{
      itemId: 'item_123',
      type: 'message',
      role: 'assistant',
      status: 'completed',
      content: [
        {
          type: 'output_audio',
          transcript: 'Thanks for calling. How can I help?',
          audio: null,
        },
      ],
    }]

When I try to load this with session.updateHistory, I get the following error:

 Error [ERR_UNHANDLED_ERROR]: Unhandled error. ({
   type: 'error',
   error: {
     type: 'error',
     event_id: 'event_D8sDiiDisPUHKG1YVD3Cl',
     error: {
       type: 'invalid_request_error',
       code: 'missing_required_parameter',
       message: "Missing required parameter: 'item.content[0].text'.",
       param: 'item.content[0].text',
       event_id: null
     }
   }
 })

Debug information

• Agents SDK version: v0.4.8
• Runtime environment Node.js v22.20.0

Repro steps

    const myItem = {
      itemId: 'item_123',
      type: 'message' as const,
      role: 'assistant' as const,
      status: 'completed' as const,
      content: [
        {
          type: 'output_audio' as const,
          transcript: 'Thanks for calling. How can I help?',
          audio: null,
        },
      ],
    };
    session.updateHistory([myItem]);

Expected behavior

I'd like to be able to restore a conversation with the exact data structures in session.history (function calls aside)

In the meantime, if anyone knows what format updateHistory accepts, that would be a great workaround

[seratch]

Thanks for the detailed repro. This is a valid issue.

session.history can include assistant audio turns (content.type === "output_audio"), but session.updateHistory() replays items through the Realtime conversation.item.create path. That API currently does not support recreating assistant audio messages, so the server expects text content and returns errors like "Missing required parameter: item.content[0].text". So today, history is not fully round-trippable into updateHistory when assistant audio items are present.

Workaround for now:

• Convert assistant output_audio items to text items using transcript, or
• Drop assistant audio items before calling updateHistory.

Hope this clarifies things.