bytedance/deer-flow · warning · HTTPException

Unsupported context_mode

Error message

Unsupported context_mode

What it means

Raised as HTTP 422 by POST /api/scheduled-tasks when body.context_mode is not one of the two supported values: 'fresh_thread_per_run' or 'reuse_thread'. It is a free-form string field validated in the handler, not by the Pydantic model, so bad values reach this check.

Source

Thrown at backend/app/gateway/routers/scheduled_tasks.py:78

async def list_scheduled_tasks(request: Request):
    repo = get_scheduled_task_repo(request)
    user = await get_optional_user_from_request(request)
    if user is None:
        return []
    return await repo.list_by_user(str(user.id))


@router.post("/scheduled-tasks")
@require_permission("threads", "write")
async def create_scheduled_task(request: Request, body: ScheduledTaskCreateRequest):
    config = get_config()
    repo = get_scheduled_task_repo(request)
    thread_store = get_thread_store(request)
    user = await get_optional_user_from_request(request)
    if user is None:
        raise HTTPException(status_code=401, detail="Authentication required")
    if body.context_mode not in {"fresh_thread_per_run", "reuse_thread"}:
        raise HTTPException(status_code=422, detail="Unsupported context_mode")
    if body.context_mode == "reuse_thread":
        if not body.thread_id:
            raise HTTPException(status_code=422, detail="reuse_thread requires thread_id")
        if not await thread_store.check_access(body.thread_id, str(user.id), require_existing=True):
            raise HTTPException(status_code=404, detail="Thread not found")
    if body.schedule_type not in {"once", "cron"}:
        raise HTTPException(status_code=422, detail="Unsupported schedule_type")

    schedule_spec = dict(body.schedule_spec)
    try:
        validate_timezone(body.timezone)
        if body.schedule_type == "cron":
            raw_cron = schedule_spec.get("cron")
            if not isinstance(raw_cron, str):
                raise HTTPException(status_code=422, detail="cron schedule requires schedule_spec.cron")
            schedule_spec["cron"] = normalize_cron_expression(raw_cron)
        next_run_at = compute_next_run_at(
            body.schedule_type,

View on GitHub (pinned to 1dd6ba1acb)

Solutions

1. Set context_mode to exactly 'fresh_thread_per_run' or 'reuse_thread'.
2. If reusing a thread, also supply thread_id (see the separate 422).
3. Pin the client against the backend's supported values — check the ScheduledTaskCreateRequest schema via /docs (OpenAPI).

Example fix

// before
{ "context_mode": "fresh-thread-per-run", ... }
// after
{ "context_mode": "fresh_thread_per_run", ... }

VALID_CONTEXT_MODES = {"fresh_thread_per_run", "reuse_thread"}
assert body["context_mode"] in VALID_CONTEXT_MODES, f"use one of {VALID_CONTEXT_MODES}"

type ContextMode = "fresh_thread_per_run" | "reuse_thread";
const isContextMode = (v: unknown): v is ContextMode =>
  v === "fresh_thread_per_run" || v === "reuse_thread";

When it happens

Trigger: Creating a task with context_mode omitted-but-overridden, misspelled ('fresh-thread-per-run'), or an unsupported value like 'shared'.

Common situations: Client written against older/newer API docs; hand-crafted JSON payloads; enum drift between frontend and backend versions.

Related errors

• reuse_thread requires thread_id
• Unsupported schedule_type
• cron schedule requires schedule_spec.cron
• {exc}
• once schedule must be in the future

AI-assisted analysis of bytedance/deer-flow@1dd6ba1acb (2026-08-14). Data as JSON: /api/errors/ee9140025887bbe6. Report an issue: GitHub.