bytedance/deer-flow · error · HTTPException

after_seq is not supported by this backward-only endpoint

Error message

after_seq is not supported by this backward-only endpoint

What it means

Error "after_seq is not supported by this backward-only endpoint" thrown in bytedance/deer-flow.

Source

Thrown at backend/app/gateway/routers/thread_runs.py:1353

    # multi-step turn (#4152). The legacy ``GET /messages`` and ``/history``
    # endpoints already use ``stamp_turn_duration_on_last_ai``; the page
    # endpoint was inlining the equivalent loop but stamping every AI row,
    # which #4163 fixed for the other paths and missed here.
    stamp_turn_duration_on_last_ai(data, run_durations)
    return data


@router.get("/{thread_id}/messages/page", response_model=ThreadMessagesPageResponse)
@require_permission("runs", "read", owner_check=True)
async def list_thread_messages_page(
    thread_id: ThreadId,
    request: Request,
    limit: int = Query(default=50, ge=1, le=200),
    before_seq: int | None = Query(default=None, ge=1),
) -> ThreadMessagesPageResponse:
    """Return a backward page ordered by the thread-global event sequence."""
    if "after_seq" in request.query_params:
        raise HTTPException(status_code=422, detail="after_seq is not supported by this backward-only endpoint")

    user_id = await get_current_user(request)
    rows, has_more = await _scan_thread_message_page(
        thread_id,
        limit=limit,
        before_seq=before_seq,
        request=request,
        user_id=user_id,
    )
    data = await _enrich_thread_message_page(thread_id, rows, request=request, user_id=user_id)
    return ThreadMessagesPageResponse(
        data=data,
        has_more=has_more,
        next_before_seq=data[0]["seq"] if has_more else None,
    )


@router.get("/{thread_id}/runs/{run_id}/messages")

View on GitHub (pinned to 1dd6ba1acb)

Solutions

1. Use before_seq for paging backwards; this endpoint only supports backward pagination.
2. Remove after_seq from the request.

When it happens

Trigger: Thrown at backend/app/gateway/routers/thread_runs.py:1353 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bytedance/deer-flow@1dd6ba1acb (2026-08-14). Data as JSON: /api/errors/d2d192cac94f0609. Report an issue: GitHub.