Fix: Emit tool_called events immediately in streaming runs

[habema]

Summary

Resolves #1282

The Solution

The implementation has been updated to emit the semantic tool_called event as soon as the first streaming chunk indicating a tool call is received from the model.

1. The _run_single_turn_streamed method now inspects raw ResponseOutputItemAddedEvent events as they arrive. If an event's item is a tool call, a corresponding RunItemStreamEvent(name="tool_called") is immediately constructed and put on the queue.

2. To avoid sending a duplicate event when the full turn results are processed at the end of the stream, a set of emitted_tool_call_ids is maintained for the duration of the turn.

3. The check for whether an event item is a tool call has been refactored. Instead of using a long, hardcoded tuple of types, it now dynamically creates this tuple from the ToolCallItemTypes alias.

[seratch]

Thanks for sending this. It seems this PR modifies the lines of code also changed by #974, which already looks good to me. @rm-openai can you take a look at #974 first and then can you share what you think about this PR?

[habema]

@seratch My apologies for the duplicate work.

After looking at both, I think this approach might have a couple of advantages:

• Instead of waiting for the model's full response to finish, this implementation emits the tool_called event the instant the first tool-call chunk arrives in the stream.
• From a maintainability perspective, it also dynamically checks for any tool-call type, so the code won't need to be updated when more tools are added down the line.

This should make the UI feel more responsive, and the code change itself is a bit smaller and more contained. Happy to chat about it or defer to the other solution if that's preferred.

[github-actions]

This PR is stale because it has been open for 10 days with no activity.

[habema]

Hey @seratch @rm-openai.
Merging #974 resolves this problem, but I still see some advantages/improvements in this implementation. Would it be possible to take a look at it, and either go forward with it or close it.

[seratch]

While I am confident #974 works well, I am not sure if your code here works without any issues. Would it be possible to enhance the current code with #974 to produce "tool_called" events as you intend here?

[habema]

It doesnt. There are merge conflicts that were caused by merging #974. I'll fix them briefly.