feat(scheduler): let scheduled tasks pin a custom agent (#5288)

* feat(scheduler): let scheduled tasks pin a custom agent

Create and update accept optional assistant_id, defaulting to lead_agent.
Custom names are normalized and must already exist for the task owner.
The workspace form exposes the same choice, and duplicate copies it.

Fixes #5286

* fix(scheduler): keep assistant-id PR free of interval tests

Drop the six interval tests that belonged to the interval schedule PR
and fail here because this tree still only accepts once/cron.

Treat lead_agent case-insensitively so LEAD_AGENT / lead-agent store
as the default. Omit unchanged assistant_id on edit so a deleted custom
agent does not 422 unrelated PATCH (rename, reschedule).

* fix(scheduler): format task page and browser tests

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

CHANGELOG.md

@@ -118,6 +118,10 @@ This section accumulates work toward the **2.1.0** milestone
 
 #### Agents & runtime
 
+- **scheduler:** Scheduled tasks can pin `assistant_id` to `lead_agent` (the
+  default) or a custom agent the owner already has. Unknown or malformed names
+  return 422. The workspace create/edit form exposes the same choice.
+  ([#5286])
 - **gateway:** `GET /api/threads/{thread_id}/runs/page` walks thread run history
   with a `(created_at, run_id)` keyset cursor (`{data, has_more,
   next_before_created_at, next_before_run_id}`). `GET /api/threads/{thread_id}/runs`

README.md

@@ -1533,6 +1533,7 @@ Current MVP capabilities:
 
 - Manage tasks at `/workspace/scheduled-tasks`
 - Choose whether each scheduled task reuses a thread and its conversation history or creates a fresh thread per run
+- Pin each task to `lead_agent` (default) or a custom agent the owner already has; unknown names are rejected
 - Duplicate an existing task into the create form as an editable draft without copying its run history
 - Support `once` and `cron` schedules
 - Run background scheduled executions as non-interactive DeerFlow runs (`ask_clarification` is not exposed there)

README_zh.md

@@ -816,6 +816,7 @@ DeerFlow 现在在 workspace 里内置了一个一等的定时任务（scheduled
 
 - 在 `/workspace/scheduled-tasks` 管理任务
 - 每个定时任务可以选择复用同一个 thread 及其历史对话，也可以选择每次运行新建一个 thread
+- 每个任务可以固定使用 `lead_agent`（默认）或当前用户已有的自定义 agent；未知名字会被拒绝
 - 将现有任务复制到创建表单中作为可编辑草稿，不复制运行历史
 - 支持 `once` 和 `cron` 两种调度方式
 - 后台定时执行以非交互式 DeerFlow run 运行（那里不会暴露 `ask_clarification`）

backend/app/gateway/routers/scheduled_tasks.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 import uuid
 from datetime import UTC, datetime
 from typing import Any
@@ -16,6 +17,7 @@ from app.gateway.deps import (
     get_scheduled_task_service,
     get_thread_store,
 )
+from deerflow.config.agents_config import AGENT_NAME_PATTERN, load_agent_config
 from deerflow.persistence.scheduled_tasks import ActiveScheduledTaskMutationConflict
 from deerflow.scheduler.schedules import (
     next_run_at as compute_next_run_at,
@@ -28,6 +30,8 @@ from deerflow.utils.thread_id import ThreadId
 
 router = APIRouter(prefix="/api", tags=["scheduled-tasks"])
 
+_DEFAULT_ASSISTANT_ID = "lead_agent"
+
 
 def _active_occurrence_conflict_detail(status: str) -> str:
     detail = f"Scheduled task has an active {status} occurrence; retry after it finishes"
@@ -36,6 +40,36 @@ def _active_occurrence_conflict_detail(status: str) -> str:
     return detail
 
 
+async def resolve_scheduled_task_assistant_id(raw: str | None, *, user_id: str) -> str:
+    """Return a stored assistant id, defaulting to lead_agent.
+
+    Custom names are normalized the same way IM/run creation already does
+    (lowercase, underscore to hyphen) and must exist for this owner.
+    """
+    if raw is None:
+        return _DEFAULT_ASSISTANT_ID
+    value = raw.strip()
+    if not value:
+        raise HTTPException(status_code=422, detail="assistant_id must not be empty")
+    normalized = value.lower().replace("_", "-")
+    if normalized == _DEFAULT_ASSISTANT_ID.replace("_", "-"):
+        return _DEFAULT_ASSISTANT_ID
+    if not AGENT_NAME_PATTERN.fullmatch(normalized):
+        raise HTTPException(
+            status_code=422,
+            detail=(f"Invalid assistant_id {raw!r}. Use 'lead_agent' or a custom agent name containing only letters, digits, and hyphens."),
+        )
+    try:
+        config = await asyncio.to_thread(load_agent_config, normalized, user_id=user_id)
+    except FileNotFoundError as exc:
+        raise HTTPException(status_code=422, detail=f"Unknown assistant_id {raw!r}") from exc
+    except ValueError as exc:
+        raise HTTPException(status_code=422, detail=str(exc)) from exc
+    if config is None:
+        raise HTTPException(status_code=422, detail=f"Unknown assistant_id {raw!r}")
+    return normalized
+
+
 async def _ensure_task_mutable(task: dict[str, Any], repo) -> None:
     if task.get("status") == "running":
         raise HTTPException(
@@ -53,6 +87,7 @@ async def _ensure_task_mutable(task: dict[str, Any], repo) -> None:
 class ScheduledTaskCreateRequest(BaseModel):
     thread_id: ThreadId | None = None
     context_mode: str = "fresh_thread_per_run"
+    assistant_id: str | None = Field(default=None, min_length=1)
     title: str = Field(min_length=1)
     prompt: str = Field(min_length=1)
     schedule_type: str
@@ -63,6 +98,7 @@ class ScheduledTaskCreateRequest(BaseModel):
 class ScheduledTaskUpdateRequest(BaseModel):
     context_mode: str | None = None
     thread_id: ThreadId | None = None
+    assistant_id: str | None = Field(default=None, min_length=1)
     title: str | None = Field(default=None, min_length=1)
     prompt: str | None = Field(default=None, min_length=1)
     schedule_spec: dict[str, Any] | None = None
@@ -124,12 +160,16 @@ async def create_scheduled_task(request: Request, body: ScheduledTaskCreateReque
             detail=(f"once schedule must be at least {config.scheduler.min_once_delay_seconds} seconds in the future"),
         )
 
+    assistant_id = await resolve_scheduled_task_assistant_id(
+        body.assistant_id,
+        user_id=str(user.id),
+    )
     return await repo.create(
         task_id=f"task-{uuid.uuid4().hex}",
         user_id=str(user.id),
         thread_id=body.thread_id,
         context_mode=body.context_mode,
-        assistant_id="lead_agent",
+        assistant_id=assistant_id,
         title=body.title,
         prompt=body.prompt,
         schedule_type=body.schedule_type,
@@ -167,6 +207,11 @@ async def update_scheduled_task(task_id: str, request: Request, body: ScheduledT
     await _ensure_task_mutable(existing, repo)
 
     updates = body.model_dump(exclude_none=True)
+    if "assistant_id" in updates:
+        updates["assistant_id"] = await resolve_scheduled_task_assistant_id(
+            updates["assistant_id"],
+            user_id=str(user.id),
+        )
     if "context_mode" in updates:
         if updates["context_mode"] not in {"fresh_thread_per_run", "reuse_thread"}:
             raise HTTPException(status_code=422, detail="Unsupported context_mode")

backend/docs/CONFIGURATION.md

@@ -385,6 +385,7 @@ Notes:
 - **Upgrade note:** `scheduler.multi_instance` and its related scheduler, ownership, and run-event settings are startup-only. Restart all Gateway Pods together after changing them; a ConfigMap update without a coordinated restart leaves the running service on its previous mode.
 - Multi-worker deployments (`GATEWAY_WORKERS > 1`) must use the Postgres database backend, enable run ownership heartbeats, and set `run_events.backend: db`. SQLite silently ignores row-level locks, while memory and JSONL run-event stores are process-local and cannot enforce singleton delivery receipts across workers; startup rejects these combinations. The process-local agentic browser tool group is incompatible with multiple Gateway workers; keep `GATEWAY_WORKERS=1` while `browser_navigate` is enabled. Browser control also requires the backend `browser` extra (`cd backend && uv sync --extra browser && uv run playwright install chromium`); startup detects enabled browser config and fails fast when Playwright is missing, and `/api/features` reports `browser_control.enabled=false` until the runtime is available.
 - The MVP supports thread reuse and fresh-thread-per-run execution modes.
+- Create/update accept optional `assistant_id` (`lead_agent` by default, or an existing custom agent for the task owner).
 - The MVP supports only `once` and `cron`.
 - Manual trigger uses the same scheduled-task resource and run lifecycle.
 - Scheduled task definitions and task-run history are persisted in the application database.

backend/tests/test_scheduled_task_router_behavior.py

@@ -1,7 +1,7 @@
 import asyncio
 from datetime import UTC, datetime, timedelta
 from types import SimpleNamespace
-from unittest.mock import AsyncMock
+from unittest.mock import AsyncMock, patch
 
 import pytest
 from _router_auth_helpers import call_unwrapped
@@ -73,6 +73,7 @@ class _Repo:
             "user_id": kwargs["user_id"],
             "thread_id": kwargs["thread_id"],
             "context_mode": kwargs["context_mode"],
+            "assistant_id": kwargs.get("assistant_id"),
             "title": kwargs["title"],
             "prompt": kwargs["prompt"],
             "schedule_type": kwargs["schedule_type"],
@@ -202,6 +203,7 @@ async def test_create_scheduled_task_uses_repo():
 
     assert created["title"] == "Daily summary"
     assert created["user_id"] == "user-1"
+    assert created["assistant_id"] == "lead_agent"
     assert created["next_run_at"] == datetime(2027, 1, 1, 1, 0, tzinfo=UTC)
 
 
@@ -940,3 +942,216 @@ async def test_update_terminal_once_task_with_future_run_at_rearms_it():
 
     assert result["status"] == "enabled"
     assert result["next_run_at"] is not None
+
+
+def _create_request(**overrides):
+    kwargs = {
+        "title": "Daily summary",
+        "prompt": "Summarize thread",
+        "schedule_type": "cron",
+        "schedule_spec": {"cron": "0 9 * * *"},
+        "timezone": "UTC",
+    }
+    kwargs.update(overrides)
+    return scheduled_tasks.ScheduledTaskCreateRequest(**kwargs)
+
+
+async def _call_create(body, repo=None):
+    repo = repo or _Repo()
+    user = SimpleNamespace(id="user-1")
+    thread_store = SimpleNamespace(check_access=AsyncMock(return_value=True))
+    old_repo = scheduled_tasks.get_scheduled_task_repo
+    old_thread_store = scheduled_tasks.get_thread_store
+    old_config = scheduled_tasks.get_config
+    old_user = scheduled_tasks.get_optional_user_from_request
+    try:
+        scheduled_tasks.get_scheduled_task_repo = lambda _request: repo
+        scheduled_tasks.get_thread_store = lambda _request: thread_store
+        scheduled_tasks.get_config = lambda: _Config()
+        scheduled_tasks.get_optional_user_from_request = AsyncMock(return_value=user)
+        return await call_unwrapped(
+            scheduled_tasks.create_scheduled_task,
+            request=SimpleNamespace(),
+            body=body,
+        )
+    finally:
+        scheduled_tasks.get_scheduled_task_repo = old_repo
+        scheduled_tasks.get_thread_store = old_thread_store
+        scheduled_tasks.get_config = old_config
+        scheduled_tasks.get_optional_user_from_request = old_user
+
+
+@pytest.mark.asyncio
+async def test_create_explicit_lead_agent_is_accepted():
+    created = await _call_create(_create_request(assistant_id="lead_agent"))
+    assert created["assistant_id"] == "lead_agent"
+
+
+@pytest.mark.asyncio
+async def test_create_lead_agent_is_accepted_case_insensitively():
+    # Callers writing LEAD_AGENT / lead-agent mean the default, not a custom agent.
+    for raw in ("LEAD_AGENT", "Lead_Agent", "lead-agent"):
+        created = await _call_create(_create_request(assistant_id=raw))
+        assert created["assistant_id"] == "lead_agent"
+
+
+@pytest.mark.asyncio
+async def test_create_custom_assistant_id_is_normalized_and_persisted():
+    with patch(
+        "app.gateway.routers.scheduled_tasks.load_agent_config",
+        return_value=object(),
+    ) as loader:
+        created = await _call_create(_create_request(assistant_id="Research_Bot"))
+    assert created["assistant_id"] == "research-bot"
+    loader.assert_called_once_with("research-bot", user_id="user-1")
+
+
+@pytest.mark.asyncio
+async def test_create_unknown_assistant_id_is_rejected():
+    with patch(
+        "app.gateway.routers.scheduled_tasks.load_agent_config",
+        side_effect=FileNotFoundError("missing"),
+    ):
+        with pytest.raises(HTTPException) as exc_info:
+            await _call_create(_create_request(assistant_id="missing-bot"))
+    assert exc_info.value.status_code == 422
+    assert "Unknown assistant_id" in exc_info.value.detail
+
+
+@pytest.mark.asyncio
+async def test_create_invalid_assistant_id_is_rejected():
+    with pytest.raises(HTTPException) as exc_info:
+        await _call_create(_create_request(assistant_id="bad agent"))
+    assert exc_info.value.status_code == 422
+    assert "Invalid assistant_id" in exc_info.value.detail
+
+
+@pytest.mark.asyncio
+async def test_update_custom_assistant_id_is_persisted():
+    repo = _Repo()
+    task = await repo.create(
+        task_id="task-1",
+        user_id="user-1",
+        thread_id=None,
+        context_mode="fresh_thread_per_run",
+        assistant_id="lead_agent",
+        title="Daily summary",
+        prompt="Summarize thread",
+        schedule_type="cron",
+        schedule_spec={"cron": "0 9 * * *"},
+        timezone="UTC",
+        next_run_at=None,
+    )
+    old_repo = scheduled_tasks.get_scheduled_task_repo
+    old_config = scheduled_tasks.get_config
+    old_user = scheduled_tasks.get_optional_user_from_request
+    try:
+        scheduled_tasks.get_scheduled_task_repo = lambda _request: repo
+        scheduled_tasks.get_config = lambda: _Config()
+        scheduled_tasks.get_optional_user_from_request = AsyncMock(return_value=SimpleNamespace(id="user-1"))
+        with patch(
+            "app.gateway.routers.scheduled_tasks.load_agent_config",
+            return_value=object(),
+        ):
+            updated = await call_unwrapped(
+                scheduled_tasks.update_scheduled_task,
+                task_id=task["id"],
+                request=SimpleNamespace(),
+                body=scheduled_tasks.ScheduledTaskUpdateRequest(assistant_id="triage-bot"),
+            )
+    finally:
+        scheduled_tasks.get_scheduled_task_repo = old_repo
+        scheduled_tasks.get_config = old_config
+        scheduled_tasks.get_optional_user_from_request = old_user
+    assert updated["assistant_id"] == "triage-bot"
+
+
+async def _seed_task(repo: _Repo, **overrides):
+    kwargs = {
+        "task_id": "task-1",
+        "user_id": "user-1",
+        "thread_id": None,
+        "context_mode": "fresh_thread_per_run",
+        "assistant_id": "lead_agent",
+        "title": "Daily summary",
+        "prompt": "Summarize thread",
+        "schedule_type": "cron",
+        "schedule_spec": {"cron": "0 9 * * *"},
+        "timezone": "UTC",
+        "next_run_at": None,
+    }
+    kwargs.update(overrides)
+    return await repo.create(**kwargs)
+
+
+async def _call_update(repo: _Repo, task_id: str, body):
+    old_repo = scheduled_tasks.get_scheduled_task_repo
+    old_config = scheduled_tasks.get_config
+    old_user = scheduled_tasks.get_optional_user_from_request
+    try:
+        scheduled_tasks.get_scheduled_task_repo = lambda _request: repo
+        scheduled_tasks.get_config = lambda: _Config()
+        scheduled_tasks.get_optional_user_from_request = AsyncMock(return_value=SimpleNamespace(id="user-1"))
+        return await call_unwrapped(
+            scheduled_tasks.update_scheduled_task,
+            task_id=task_id,
+            request=SimpleNamespace(),
+            body=body,
+        )
+    finally:
+        scheduled_tasks.get_scheduled_task_repo = old_repo
+        scheduled_tasks.get_config = old_config
+        scheduled_tasks.get_optional_user_from_request = old_user
+
+
+@pytest.mark.asyncio
+async def test_update_unknown_assistant_id_is_rejected():
+    repo = _Repo()
+    task = await _seed_task(repo)
+    with patch(
+        "app.gateway.routers.scheduled_tasks.load_agent_config",
+        side_effect=FileNotFoundError("missing"),
+    ):
+        with pytest.raises(HTTPException) as exc_info:
+            await _call_update(
+                repo,
+                task["id"],
+                scheduled_tasks.ScheduledTaskUpdateRequest(assistant_id="missing-bot"),
+            )
+    assert exc_info.value.status_code == 422
+    assert "Unknown assistant_id" in exc_info.value.detail
+    assert repo.items[task["id"]]["assistant_id"] == "lead_agent"
+
+
+@pytest.mark.asyncio
+async def test_update_invalid_assistant_id_is_rejected():
+    repo = _Repo()
+    task = await _seed_task(repo)
+    with pytest.raises(HTTPException) as exc_info:
+        await _call_update(
+            repo,
+            task["id"],
+            scheduled_tasks.ScheduledTaskUpdateRequest(assistant_id="bad agent"),
+        )
+    assert exc_info.value.status_code == 422
+    assert "Invalid assistant_id" in exc_info.value.detail
+
+
+@pytest.mark.asyncio
+async def test_update_omitting_assistant_id_keeps_existing_even_if_agent_is_gone():
+    # Unrelated PATCH (rename, reschedule) must not re-resolve assistant_id.
+    # Otherwise a since-deleted custom agent makes the task uneditable.
+    repo = _Repo()
+    task = await _seed_task(repo, assistant_id="research-bot")
+    with patch(
+        "app.gateway.routers.scheduled_tasks.load_agent_config",
+        side_effect=FileNotFoundError("missing"),
+    ) as loader:
+        updated = await _call_update(
+            repo,
+            task["id"],
+            scheduled_tasks.ScheduledTaskUpdateRequest(title="Renamed"),
+        )
+    loader.assert_not_called()
+    assert updated["title"] == "Renamed"
+    assert updated["assistant_id"] == "research-bot"

frontend/src/app/workspace/scheduled-tasks/page.tsx

@@ -1,8 +1,9 @@
 "use client";
 
+import { useQuery } from "@tanstack/react-query";
 import { CopyIcon, TriangleAlertIcon } from "lucide-react";
 import { useSearchParams } from "next/navigation";
-import { useEffect, useRef, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 
 import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
 import { Button } from "@/components/ui/button";
@@ -15,6 +16,13 @@ import {
   DialogTitle,
 } from "@/components/ui/dialog";
 import { Input } from "@/components/ui/input";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/components/ui/select";
 import { Textarea } from "@/components/ui/textarea";
 import {
   ScheduledTaskScheduleInput,
@@ -25,6 +33,8 @@ import {
   WorkspaceContainer,
   WorkspaceHeader,
 } from "@/components/workspace/workspace-container";
+import { listAgents } from "@/core/agents/api";
+import { useAgentsApiEnabled } from "@/core/agents/hooks";
 import { useI18n } from "@/core/i18n/hooks";
 import {
   useCreateScheduledTask,
@@ -82,6 +92,18 @@ function formatTimestamp(value: string | null, locale: string): string {
   }).format(date);
 }
 
+const DEFAULT_ASSISTANT_ID = "lead_agent";
+
+function agentDisplayName(
+  assistantId: string | null | undefined,
+  leadLabel: string,
+): string {
+  if (!assistantId || assistantId === DEFAULT_ASSISTANT_ID) {
+    return leadLabel;
+  }
+  return assistantId;
+}
+
 export default function ScheduledTasksPage() {
   const { t, locale } = useI18n();
   const st = t.scheduledTasks;
@@ -89,6 +111,14 @@ export default function ScheduledTasksPage() {
   const threadId = searchParams.get("thread_id");
   const allTasksQuery = useScheduledTasks();
   const threadTasksQuery = useThreadScheduledTasks(threadId);
+  const { enabled: agentsApiEnabled, isLoading: agentsApiLoading } =
+    useAgentsApiEnabled();
+  const agentsQuery = useQuery({
+    queryKey: ["agents"],
+    queryFn: listAgents,
+    enabled: !agentsApiLoading && agentsApiEnabled,
+    retry: false,
+  });
   const data = threadId ? threadTasksQuery.data : allTasksQuery.data;
   const queryError = threadId ? threadTasksQuery.error : allTasksQuery.error;
   const [deleteOpen, setDeleteOpen] = useState(false);
@@ -99,6 +129,8 @@ export default function ScheduledTasksPage() {
   const [targetThreadId, setTargetThreadId] = useState(threadId ?? "");
   const [title, setTitle] = useState("");
   const [prompt, setPrompt] = useState("");
+  const [createAssistantId, setCreateAssistantId] =
+    useState(DEFAULT_ASSISTANT_ID);
   const [createSchedule, setCreateSchedule] = useState<ScheduleValue>({
     schedule_type: "cron",
     schedule_spec: { cron: "0 9 * * *" },
@@ -112,6 +144,7 @@ export default function ScheduledTasksPage() {
   const [editing, setEditing] = useState(false);
   const [editTitle, setEditTitle] = useState("");
   const [editPrompt, setEditPrompt] = useState("");
+  const [editAssistantId, setEditAssistantId] = useState(DEFAULT_ASSISTANT_ID);
   const [editSchedule, setEditSchedule] = useState<ScheduleValue>({
     schedule_type: "cron",
     schedule_spec: { cron: "0 9 * * *" },
@@ -120,6 +153,30 @@ export default function ScheduledTasksPage() {
   const [createNonce, setCreateNonce] = useState(0);
   const createFormRef = useRef<HTMLDivElement>(null);
   const createTitleRef = useRef<HTMLInputElement>(null);
+  const agentOptions = useMemo(() => {
+    const names = new Set((agentsQuery.data ?? []).map((agent) => agent.name));
+    const options = [
+      {
+        value: DEFAULT_ASSISTANT_ID,
+        label: st.create.leadAgent,
+      },
+      ...(agentsQuery.data ?? [])
+        .filter((agent) => agent.name !== DEFAULT_ASSISTANT_ID)
+        .map((agent) => ({ value: agent.name, label: agent.name })),
+    ];
+    for (const extra of [createAssistantId, editAssistantId]) {
+      if (extra && extra !== DEFAULT_ASSISTANT_ID && !names.has(extra)) {
+        options.push({ value: extra, label: extra });
+        names.add(extra);
+      }
+    }
+    return options;
+  }, [
+    agentsQuery.data,
+    createAssistantId,
+    editAssistantId,
+    st.create.leadAgent,
+  ]);
   const filteredData = (data ?? []).filter((task) => {
     const statusPass = statusFilter === "all" || task.status === statusFilter;
     const typePass = typeFilter === "all" || task.schedule_type === typeFilter;
@@ -170,6 +227,7 @@ export default function ScheduledTasksPage() {
     setPrompt(task.prompt);
     setContextMode(task.context_mode);
     setTargetThreadId(task.thread_id ?? "");
+    setCreateAssistantId(task.assistant_id ?? DEFAULT_ASSISTANT_ID);
     setCreateSchedule({
       schedule_type: task.schedule_type,
       schedule_spec: { ...task.schedule_spec },
@@ -208,6 +266,7 @@ export default function ScheduledTasksPage() {
     }
     setEditTitle(selectedTask.title);
     setEditPrompt(selectedTask.prompt);
+    setEditAssistantId(selectedTask.assistant_id ?? DEFAULT_ASSISTANT_ID);
     const spec = selectedTask.schedule_spec as {
       cron?: string;
       run_at?: string;
@@ -287,6 +346,25 @@ export default function ScheduledTasksPage() {
                 />
               </>
             )}
+            <Select
+              value={createAssistantId}
+              onValueChange={setCreateAssistantId}
+            >
+              <SelectTrigger
+                className="w-full"
+                data-testid="scheduled-task-create-agent"
+                aria-label={st.create.agent}
+              >
+                <SelectValue placeholder={st.create.agent} />
+              </SelectTrigger>
+              <SelectContent>
+                {agentOptions.map((option) => (
+                  <SelectItem key={option.value} value={option.value}>
+                    {option.label}
+                  </SelectItem>
+                ))}
+              </SelectContent>
+            </Select>
             <Input
               ref={createTitleRef}
               value={title}
@@ -327,6 +405,7 @@ export default function ScheduledTasksPage() {
                     context_mode: contextMode,
                     thread_id:
                       contextMode === "reuse_thread" ? targetThreadId : null,
+                    assistant_id: createAssistantId,
                     title,
                     prompt,
                     schedule_type: createSchedule.schedule_type,
@@ -339,6 +418,7 @@ export default function ScheduledTasksPage() {
                       setTitle("");
                       setPrompt("");
                       setTargetThreadId("");
+                      setCreateAssistantId(DEFAULT_ASSISTANT_ID);
                       setContextMode("fresh_thread_per_run");
                       setCreateSchedule({
                         schedule_type: "cron",
@@ -481,6 +561,13 @@ export default function ScheduledTasksPage() {
                     {st.detail.contextMode}:{" "}
                     {contextModeLabel(selectedTask.context_mode)}
                   </div>
+                  <div className="text-muted-foreground text-sm">
+                    {st.detail.agent}:{" "}
+                    {agentDisplayName(
+                      selectedTask.assistant_id,
+                      st.create.leadAgent,
+                    )}
+                  </div>
                   <div className="text-muted-foreground text-sm">
                     {selectedTask.context_mode === "reuse_thread"
                       ? `${st.detail.thread}: ${selectedTask.thread_id ?? NONE}`
@@ -523,6 +610,25 @@ export default function ScheduledTasksPage() {
                         onChange={(event) => setEditPrompt(event.target.value)}
                         placeholder={st.edit.promptPlaceholder}
                       />
+                      <Select
+                        value={editAssistantId}
+                        onValueChange={setEditAssistantId}
+                      >
+                        <SelectTrigger
+                          className="w-full"
+                          data-testid="scheduled-task-edit-agent"
+                          aria-label={st.create.agent}
+                        >
+                          <SelectValue placeholder={st.create.agent} />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {agentOptions.map((option) => (
+                            <SelectItem key={option.value} value={option.value}>
+                              {option.label}
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
                       <ScheduledTaskScheduleInput
                         key={selectedTask.id}
                         initial={editSchedule}
@@ -531,14 +637,19 @@ export default function ScheduledTasksPage() {
                       />
                       <Button
                         size="sm"
-                        onClick={() =>
+                        onClick={() => {
+                          const pinned =
+                            selectedTask.assistant_id ?? DEFAULT_ASSISTANT_ID;
                           updateTask.mutate({
                             title: editTitle,
                             prompt: editPrompt,
+                            ...(editAssistantId !== pinned
+                              ? { assistant_id: editAssistantId }
+                              : {}),
                             schedule_spec: editSchedule.schedule_spec,
                             timezone: editSchedule.timezone || "UTC",
-                          })
+                          });
-                        }
+                        }}
                         disabled={updateTask.isPending}
                       >
                         {st.edit.submit}

frontend/src/core/i18n/locales/en-US.ts

@@ -484,6 +484,8 @@ export const enUS: Translations = {
       title: "Create scheduled task",
       taskTitle: "Task title",
       prompt: "Prompt",
+      agent: "Agent",
+      leadAgent: "Default agent (lead_agent)",
       submit: "Create",
       fillRequired: "Fill all required fields",
     },
@@ -507,6 +509,7 @@ export const enUS: Translations = {
     },
     detail: {
       contextMode: "Context mode",
+      agent: "Agent",
       thread: "Thread",
       lastThread: "Last thread",
       schedule: "Schedule",

frontend/src/core/i18n/locales/types.ts

@@ -394,6 +394,8 @@ export interface Translations {
       title: string;
       taskTitle: string;
       prompt: string;
+      agent: string;
+      leadAgent: string;
       submit: string;
       fillRequired: string;
     };
@@ -416,6 +418,7 @@ export interface Translations {
     };
     detail: {
       contextMode: string;
+      agent: string;
       thread: string;
       lastThread: string;
       schedule: string;

frontend/src/core/i18n/locales/zh-CN.ts

@@ -459,6 +459,8 @@ export const zhCN: Translations = {
       title: "创建定时任务",
       taskTitle: "任务标题",
       prompt: "提示词",
+      agent: "Agent",
+      leadAgent: "默认 Agent（lead_agent）",
       submit: "创建",
       fillRequired: "请填写所有必填项",
     },
@@ -482,6 +484,7 @@ export const zhCN: Translations = {
     },
     detail: {
       contextMode: "上下文模式",
+      agent: "Agent",
       thread: "线程",
       lastThread: "上个线程",
       schedule: "调度",

frontend/src/core/scheduled-tasks/api.ts

@@ -52,6 +52,7 @@ export async function fetchScheduledTaskRuns(
 export type ScheduledTaskPayload = {
   context_mode: "fresh_thread_per_run" | "reuse_thread";
   thread_id?: string | null;
+  assistant_id?: string | null;
   title: string;
   prompt: string;
   schedule_type: "once" | "cron";

frontend/src/core/scheduled-tasks/types.ts

@@ -2,6 +2,7 @@ export type ScheduledTask = {
   id: string;
   thread_id: string | null;
   context_mode: "fresh_thread_per_run" | "reuse_thread";
+  assistant_id: string | null;
   title: string;
   prompt: string;
   schedule_type: "once" | "cron";

frontend/tests/e2e/scheduled-tasks.spec.ts

@@ -337,3 +337,124 @@ test("detail pane falls back to a visible task after filters hide the selected t
     0,
   );
 });
+
+test("create posts the default lead_agent assistant_id", async ({ page }) => {
+  let createBody: Record<string, unknown> | null = null;
+  page.on("request", (request) => {
+    if (
+      request.method() === "POST" &&
+      new URL(request.url()).pathname.endsWith("/api/scheduled-tasks")
+    ) {
+      createBody = request.postDataJSON() as Record<string, unknown>;
+    }
+  });
+  mockLangGraphAPI(page, { threads: [], scheduledTasks: [] });
+
+  await page.goto("/workspace/scheduled-tasks");
+  const createForm = page.getByTestId("scheduled-task-create-form");
+  await expect(
+    createForm.getByTestId("scheduled-task-create-agent"),
+  ).toContainText(/Default agent \(lead_agent\)/i);
+  await createForm.getByRole("button", { name: "One-time" }).click();
+  await createForm.getByLabel("Run at").fill("2026-07-02T09:00");
+  await createForm.getByPlaceholder("Task title").fill("Agent pin");
+  await createForm.getByPlaceholder("Prompt").fill("Summarize thread");
+  await createForm.getByRole("button", { name: "Create" }).click();
+  await expect(page.getByRole("button", { name: /Agent pin/i })).toBeVisible();
+  expect(createBody).toMatchObject({ assistant_id: "lead_agent" });
+  await expect(page.getByTestId("scheduled-task-detail")).toContainText(
+    /Default agent \(lead_agent\)/i,
+  );
+});
+
+test("duplicate copies the source task assistant into the create form", async ({
+  page,
+}) => {
+  mockLangGraphAPI(page, {
+    threads: [],
+    scheduledTasks: [
+      {
+        id: "task-copy-agent",
+        thread_id: null,
+        context_mode: "fresh_thread_per_run",
+        assistant_id: "research-bot",
+        title: "Research digest",
+        prompt: "Summarize papers",
+        schedule_type: "cron",
+        schedule_spec: { cron: "0 9 * * *" },
+        timezone: "UTC",
+        status: "enabled",
+        next_run_at: "2026-07-02T01:00:00+00:00",
+        last_run_at: null,
+        last_run_id: null,
+        last_error: null,
+        run_count: 0,
+        created_at: "2026-07-01T00:00:00+00:00",
+        updated_at: "2026-07-01T00:00:00+00:00",
+      },
+    ],
+  });
+
+  await page.goto("/workspace/scheduled-tasks");
+  await expect(page.getByTestId("scheduled-task-detail")).toContainText(
+    "research-bot",
+  );
+  await page
+    .getByTestId("scheduled-task-detail")
+    .getByRole("button", { name: "Duplicate" })
+    .click();
+  await expect(page.getByTestId("scheduled-task-create-agent")).toContainText(
+    "research-bot",
+  );
+});
+
+test("edit omits assistant_id when the agent is unchanged", async ({
+  page,
+}) => {
+  let patchBody: Record<string, unknown> | null = null;
+  page.on("request", (request) => {
+    if (
+      request.method() === "PATCH" &&
+      new URL(request.url()).pathname.includes("/api/scheduled-tasks/")
+    ) {
+      patchBody = request.postDataJSON() as Record<string, unknown>;
+    }
+  });
+  mockLangGraphAPI(page, {
+    threads: [],
+    scheduledTasks: [
+      {
+        id: "task-edit-agent",
+        thread_id: null,
+        context_mode: "fresh_thread_per_run",
+        assistant_id: "research-bot",
+        title: "Research digest",
+        prompt: "Summarize papers",
+        schedule_type: "cron",
+        schedule_spec: { cron: "0 9 * * *" },
+        timezone: "UTC",
+        status: "enabled",
+        next_run_at: "2026-07-02T01:00:00+00:00",
+        last_run_at: null,
+        last_run_id: null,
+        last_error: null,
+        run_count: 0,
+        created_at: "2026-07-01T00:00:00+00:00",
+        updated_at: "2026-07-01T00:00:00+00:00",
+      },
+    ],
+  });
+
+  await page.goto("/workspace/scheduled-tasks");
+  await page
+    .getByTestId("scheduled-task-detail")
+    .getByRole("button", { name: "Edit" })
+    .click();
+  await page.getByPlaceholder("Edit title").fill("Renamed digest");
+  await page.getByRole("button", { name: "Save edit" }).click();
+  await expect(page.getByTestId("scheduled-task-detail")).toContainText(
+    "Renamed digest",
+  );
+  expect(patchBody).toMatchObject({ title: "Renamed digest" });
+  expect(patchBody).not.toHaveProperty("assistant_id");
+});

frontend/tests/e2e/utils/mock-api.ts

@@ -71,6 +71,7 @@ export type MockAPIOptions = {
     id: string;
     thread_id: string | null;
     context_mode?: "fresh_thread_per_run" | "reuse_thread";
+    assistant_id?: string | null;
     last_thread_id?: string | null;
     title: string;
     prompt: string;
@@ -484,6 +485,10 @@ export function mockLangGraphAPI(page: Page, options?: MockAPIOptions) {
         context_mode:
           (payload.context_mode as "fresh_thread_per_run" | "reuse_thread") ??
           "fresh_thread_per_run",
+        assistant_id:
+          typeof payload.assistant_id === "string"
+            ? payload.assistant_id
+            : "lead_agent",
         last_thread_id: null,
         title,
         prompt,

frontend/tests/unit/core/scheduled-tasks/hooks.test.ts

@@ -80,6 +80,7 @@ describe("scheduled tasks api", () => {
     const payload: ScheduledTaskPayload = {
       context_mode: "fresh_thread_per_run",
       thread_id: null,
+      assistant_id: "research-bot",
       title: "Daily summary",
       prompt: "Summarize thread",
       schedule_type: "cron",