bytedance/deer-flow · error · HTTPException

Could not find source run for assistant message

Error message

Could not find source run for assistant message

What it means

Raised in _find_target_run_id (HTTP 409) when no run record can be linked to the assistant message being regenerated: neither the journal lookup nor the fallback scan (recent run events, bounded by REGENERATE_HISTORY_SCAN_LIMIT = 200) found a successful run whose last AI message matches. The server needs the source run_id to rerun the turn, so regenerate is refused.

Solutions

1. Regenerate the latest turn first (its run events are freshest) instead of reaching far back in history.
2. Check run-event journal retention settings and the run manager store backend; ensure runs are persisted, not in-memory only.
3. Increase REGENERATE_HISTORY_SCAN_LIMIT if the deployment regularly exceeds 200 run events between turns.
4. As a workaround, start a new thread and resurface needed context rather than regenerating a very old turn.

const runs = await listRuns(threadId, {status: 'success'});
if (!runs.some(r => r.final_message_id === targetMessageId)) {
  // regenerate the latest turn instead, or start a new thread
}

try { await regeneratePrepare(threadId, messageId); } catch (e) { if (e.status === 409 && /source run/.test(e.detail)) { await resyncThreadAndRegenerateLatest(threadId); } else throw e; }

When it happens

Trigger: Regenerating an assistant message whose producing run's event journal was trimmed beyond the 200-entry scan limit; run store persistence gap where run records were never hydrated; regenerating an old turn after 200+ newer events.

Common situations: Long threads with heavy tool activity that floods run events; restarting the Gateway with an in-memory run store so older run records were lost; run-event journal retention/pruning configured aggressively.

Related errors

• Checkpoint is missing checkpoint_id
• Could not find an addressable checkpoint before the target…
• Could not find the user message for this assistant response
• Could not locate target user message in recent checkpoint…
• Could not safely resolve the checkpoint before the target…

AI-assisted analysis of bytedance/deer-flow@1dd6ba1acb (2026-08-14). Data as JSON: /api/errors/48703e1b337f0bdd. Report an issue: GitHub.

Appendix: source

Thrown at backend/app/gateway/routers/thread_runs.py:515

        return source_run_id

    run_mgr = get_run_manager(request)
    user_id = await get_current_user(request)
    records = await run_mgr.list_by_thread(thread_id, user_id=user_id, limit=10)
    fallback_record = next(
        (record for record in records if record.status == RunStatus.success and _run_last_ai_matches_message(record, target_message)),
        None,
    )
    if fallback_record is not None:
        return fallback_record.run_id
    if len(rows) >= REGENERATE_HISTORY_SCAN_LIMIT:
        logger.warning(
            "Could not find source run for regenerate message %s in recent run events for thread %s (limit=%s)",
            message_id,
            thread_id,
            REGENERATE_HISTORY_SCAN_LIMIT,
        )
    raise HTTPException(status_code=409, detail="Could not find source run for assistant message")


async def _find_base_checkpoint_before_human(
    thread_id: str,
    human_message_id: str,
    request: Request,
    *,
    head_checkpoint: Any | None = None,
) -> Any:
    accessor, base_config = await build_thread_checkpoint_state_accessor(request, thread_id=thread_id)
    if head_checkpoint is not None:
        try:
            return await find_checkpoint_before_message(
                accessor,
                head_checkpoint,
                human_message_id,
                max_depth=REGENERATE_HISTORY_RAW_SCAN_LIMIT,
            )

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