dify - 💡(How to fix) Fix [Bug] LangSmith tracing fails with 400 "trace_id does not match first part of dotted_order" in Chatflow conversations [1 pull requests]

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Dify version

1.14.0

Cloud or Self Hosted

Self Hosted (Docker)

Steps to reproduce

1. Deploy Dify via Docker Compose (self-hosted).
2. Enable LangSmith tracing for the workspace/app — configure tracing in the app's monitoring settings.
3. Open a Chatflow app and send a message that triggers a multi-node run (LLM node + at least one downstream node, so child runs are created).
4. Watch the Dify api container logs (docker compose logs -f worker) while the conversation runs.
5. Check the LangSmith project — the trace for this conversation is missing nodes or shows broken parent/child links.

✔️ Expected Behavior

All runs from the Chatflow conversation are accepted by LangSmith and appear as a single, fully-linked trace tree (root run + child node runs) in the LangSmith project.

❌ Actual Behavior

LangSmith rejects the multipart ingest with HTTP 400. The child run's trace_id does not match the first UUID segment of its dotted_order, so the batch is dropped and the trace in LangSmith is incomplete. Full error from the api container log:

{
    "ts": "2026-05-09T09:10:21.119Z",
    "severity": "WARN",
    "service": "dify/worker",
    "caller": "client.py:3166",
    "message": "Failed to send compressed multipart ingest: langsmith.utils.LangSmithError: Failed to POST https://api.smith.langchain.com/runs/multipart in LangSmith API. HTTPError('400 Client Error: Bad Request for url: https://api.smith.langchain.com/runs/multipart', '{\"error\":\"Bad request: invalid \\'dotted_order\\': trace_id f8b1edce-ea6d-6cac-6669-e6c7552b3270 does not match first part of dotted_order 7e78ba1a-bf5a-4736-bdec-d59e0e1bb2a0 for run_id:7e78ba1a-bf5a-4736-bdec-d59e0e1bb2a0 trace_id:f8b1edce-ea6d-6cac-6669-e6c7552b3270 dotted_order:20260509T091010611260Z7e78ba1a-bf5a-4736-bdec-d59e0e1bb2a0 parent_run_id:\\\\u003cnil\\\\u003e\"}\\n')"
}