dify - 💡(How to fix) Fix Reasoning <think> content leaks into Chatflow answer in separated mode [1 pull requests]

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Dify version

main

Cloud or Self Hosted

Cloud, Self Hosted (Docker), Self Hosted (Source)

Steps to reproduce

1. In a Chatflow, add an LLM node using a reasoning model (e.g. claude-haiku-4-5, deepseek-r1) with thinking/reasoning enabled.
2. Enable the LLM node's "Enable reasoning tag separation" toggle (reasoning_format = "separated").
3. Wire the LLM output straight into the Answer node.
4. Run the app via the Service API and inspect the returned answer.

✔️ Expected Behavior

With reasoning tag separation enabled, the returned answer contains only the final answer; the <think>...</think> reasoning is stripped (and still available separately as reasoning_content).

❌ Actual Behavior

The answer still contains the raw <think>...</think> reasoning. In separated mode only the final text variable is cleaned; the per-token stream is emitted unfiltered, and Chatflow assembles its answer from that stream — so reasoning leaks through even with the toggle on.

Root cause is in the streaming path of the workflow engine (graphon); fix in progress: langgenius/graphon#171.