Capturing intermediate reasoning text between tool calls

OSS Product Help LangChain
1

Hi team! I’m building a streaming agent UI with LangChain and Azure OpenAI (GPT-5.2 with reasoning mode). I’m using astream_events(version="v2") to capture token-by-token streaming.

Setup:

  • langchain-openai with AzureChatOpenAI
  • reasoning={"effort": "high", "summary": "detailed"} and output_version="responses/v1"
  • Using astream_events to capture on_chat_model_stream events

What works:

  • Initial reasoning tokens stream correctly via content_blocks with type="reasoning"
  • Tool calls and results are captured via on_tool_start/on_tool_end
  • Final reasoning after all tools completes streams correctly

Issue:
After a tool result returns, the model often goes directly to the next tool call (tool_args tokens) without emitting visible reasoning text. I see this pattern:

reasoning tokens → tool_call → tool_result → tool_args (next tool) → tool_result → ... → reasoning tokens (final)

I expected intermediate reasoning between each tool call, similar to how ChatGPT/Claude show “thinking” text between tool invocations.

Questions:

  1. Is there a way to force/encourage the model to emit reasoning summaries between tool calls, not just at the start and end?
  2. Are there different astream_events event types I should be listening for to capture this intermediate content?
  3. Is this a model behavior limitation with the Responses API, or is there a configuration I’m missing?

Any guidance appreciated! :folded_hands:

1 Like
2

Facing the same problem with Azure OpenAI 5.2 (chat completions). Would highly appreciate someone responding to this.

Using ChatAnthropic gives intermediate reasoning.

3

Are you using Microsoft Foundry for Azure Deployment?