LangGraph: How do I read subgraph state without an interrupt? (Open Deep Research)

OSS Product Help LangGraph
1

I’m using the Open Deep Research LangGraph agent. I want to capture sources and activities that are produced inside subgraphs and persist them - ideally without using an interrupt.

My setup

  • Graph compiled with a checkpointer (MemorySaver) + thread_id.

  • Running on LangGraph Platform.

  • A FastAPI service is polling/querying the LangGraph Platform API to save sources and activities (of the research) in the database and show them in the UI.

What I’m unsure about
The research can be long (10-20 minutes)
With how this agent is built is only has a few nodes
clarify_with_user → write_reserach_brief → research_supervisor → final_report_generaion.

So currently, I can only get state updates in the UI after each of those finishes.
But the issue is that all the magic happens inside the research_supervisor subgraph.
How can I get its state during a run?

2

Hi! When streaming from the parent graph, you can set subgraphs=True to get streaming events from the subgraphs. You can see documentation here: Graphs

3

Hi @rahul-langchain , I’m a bit confused. According to this response - How can I view the state of the subgraph in the middle of the run · Issue #175 · langchain-ai/open_deep_research · GitHub , I got a confirmation of this limitation.

4

Hi! You will not receive state updates from the subgraph, but you can stream events from it using the parameter I shared.