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langchain/libs/partners/openai/tests
Dmitrii Rashchenko a43df006de Support of openai reasoning summary streaming (#30909)
**langchain_openai: Support of reasoning summary streaming**

**Description:**
OpenAI API now supports streaming reasoning summaries for reasoning
models (o1, o3, o3-mini, o4-mini). More info about it:
https://platform.openai.com/docs/guides/reasoning#reasoning-summaries

It is supported only in Responses API (not Completion API), so you need
to create LangChain Open AI model as follows to support reasoning
summaries streaming:

```
llm = ChatOpenAI(
    model="o4-mini", # also o1, o3, o3-mini support reasoning streaming
    use_responses_api=True,  # reasoning streaming works only with responses api, not completion api
    model_kwargs={
        "reasoning": {
            "effort": "high",  # also "low" and "medium" supported
            "summary": "auto"  # some models support "concise" summary, some "detailed", but auto will always work
        }
    }
)
```

Now, if you stream events from llm:

```
async for event in llm.astream_events(prompt, version="v2"):
    print(event)
```

or

```
for chunk in llm.stream(prompt):
    print (chunk)
```

OpenAI API will send you new types of events:
`response.reasoning_summary_text.added`
`response.reasoning_summary_text.delta`
`response.reasoning_summary_text.done`

These events are new, so they were ignored. So I have added support of
these events in function `_convert_responses_chunk_to_generation_chunk`,
so reasoning chunks or full reasoning added to the chunk
additional_kwargs.

Example of how this reasoning summary may be printed:

```
    async for event in llm.astream_events(prompt, version="v2"):
        if event["event"] == "on_chat_model_stream":
            chunk: AIMessageChunk = event["data"]["chunk"]
            if "reasoning_summary_chunk" in chunk.additional_kwargs:
                print(chunk.additional_kwargs["reasoning_summary_chunk"], end="")
            elif "reasoning_summary" in chunk.additional_kwargs:
                print("\n\nFull reasoning step summary:", chunk.additional_kwargs["reasoning_summary"])
            elif chunk.content and chunk.content[0]["type"] == "text":
                print(chunk.content[0]["text"], end="")
```

or

```
    for chunk in llm.stream(prompt):
        if "reasoning_summary_chunk" in chunk.additional_kwargs:
            print(chunk.additional_kwargs["reasoning_summary_chunk"], end="")
        elif "reasoning_summary" in chunk.additional_kwargs:
            print("\n\nFull reasoning step summary:", chunk.additional_kwargs["reasoning_summary"])
        elif chunk.content and chunk.content[0]["type"] == "text":
            print(chunk.content[0]["text"], end="")
```

---------

Co-authored-by: Chester Curme <chester.curme@gmail.com>
2025-04-22 14:51:13 +00:00
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