diff --git a/offline-backend-20260512/backend/tests/test_curator_scheduler_startup.py b/offline-backend-20260512/backend/tests/test_curator_scheduler_startup.py
new file mode 100644
index 00000000..c508fa17
--- /dev/null
+++ b/offline-backend-20260512/backend/tests/test_curator_scheduler_startup.py
@@ -0,0 +1,156 @@
+"""Tests that the curator scheduler does not block application startup.
+
+Verifies:
+1. _curator_scheduler_loop is launched as a non-blocking asyncio task.
+2. The scheduler sleeps for the startup delay before doing any work.
+3. maybe_run_curator is NOT called during the startup delay window.
+4. When the lock is unavailable the loop exits immediately without calling the curator.
+
+NOTE: ``import app.gateway.app as m`` resolves to the FastAPI *instance* because
+``app/gateway/__init__.py`` re-exports ``app = FastAPI(...)``.  The actual module
+object lives in ``sys.modules["app.gateway.app"]`` and is used here via a helper.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import sys
+from unittest.mock import MagicMock, patch
+
+
+def _gateway_module():
+    """Return the real app.gateway.app *module* (not the FastAPI instance)."""
+    import importlib
+    importlib.import_module("app.gateway.app")  # side-effect: populates sys.modules
+    return sys.modules["app.gateway.app"]
+
+
+_STARTUP_DELAY = 300   # matches _CURATOR_STARTUP_DELAY_SECONDS in app.gateway.app
+_CHECK_INTERVAL = 3600  # matches _CURATOR_CHECK_INTERVAL_SECONDS
+
+
+def test_scheduler_does_not_block_startup():
+    """create_task must return immediately — startup must not await the loop body."""
+    mod = _gateway_module()
+    curator_called = False
+
+    async def fake_sleep(_delay):
+        pass
+
+    async def fake_curator():
+        nonlocal curator_called
+        curator_called = True
+
+    async def run():
+        with (
+            patch.object(mod, "_acquire_singleton_lock", return_value=MagicMock()),
+            patch.object(mod, "_release_singleton_lock"),
+            patch.object(mod, "_CURATOR_STARTUP_DELAY_SECONDS", _STARTUP_DELAY),
+            patch.object(mod, "_CURATOR_CHECK_INTERVAL_SECONDS", _CHECK_INTERVAL),
+            patch("deerflow.skills.curator.maybe_run_curator", fake_curator),
+            patch("asyncio.sleep", fake_sleep),
+        ):
+            task = asyncio.create_task(mod._curator_scheduler_loop())
+            # create_task must return immediately; the coroutine is still pending
+            assert not task.done(), "task should be running in the background, not finished"
+            task.cancel()
+            try:
+                await task
+            except asyncio.CancelledError:
+                pass
+
+    asyncio.run(run())
+    assert not curator_called, "curator must not fire before the startup delay completes"
+
+
+def test_scheduler_sleeps_startup_delay_before_first_curator_call():
+    """The very first asyncio.sleep must use the startup-delay value (300 s)."""
+    mod = _gateway_module()
+    sleep_calls: list[float] = []
+    curator_called = False
+
+    async def fake_sleep(delay):
+        sleep_calls.append(delay)
+        raise asyncio.CancelledError  # stop after recording first sleep
+
+    async def fake_curator():
+        nonlocal curator_called
+        curator_called = True
+
+    async def run():
+        with (
+            patch.object(mod, "_acquire_singleton_lock", return_value=MagicMock()),
+            patch.object(mod, "_release_singleton_lock"),
+            patch.object(mod, "_CURATOR_STARTUP_DELAY_SECONDS", _STARTUP_DELAY),
+            patch.object(mod, "_CURATOR_CHECK_INTERVAL_SECONDS", _CHECK_INTERVAL),
+            patch("deerflow.skills.curator.maybe_run_curator", fake_curator),
+            patch("asyncio.sleep", fake_sleep),
+        ):
+            task = asyncio.create_task(mod._curator_scheduler_loop())
+            try:
+                await task
+            except asyncio.CancelledError:
+                pass
+
+    asyncio.run(run())
+
+    assert sleep_calls, "asyncio.sleep was never called"
+    assert sleep_calls[0] == _STARTUP_DELAY, (
+        f"first sleep must be the startup delay ({_STARTUP_DELAY}s), got {sleep_calls[0]}"
+    )
+    assert not curator_called, "curator must not be called before startup delay elapses"
+
+
+def test_scheduler_actually_calls_curator_after_startup_delay():
+    """After the startup delay elapses, maybe_run_curator must be called."""
+    mod = _gateway_module()
+    curator_call_count = 0
+
+    async def fake_sleep(*_):
+        pass  # instant — simulate time passing
+
+    async def fake_curator():
+        nonlocal curator_call_count
+        curator_call_count += 1
+        # After first call cancel the loop so the test terminates
+        raise asyncio.CancelledError
+
+    async def run():
+        with (
+            patch.object(mod, "_acquire_singleton_lock", return_value=MagicMock()),
+            patch.object(mod, "_release_singleton_lock"),
+            patch.object(mod, "_CURATOR_STARTUP_DELAY_SECONDS", _STARTUP_DELAY),
+            patch.object(mod, "_CURATOR_CHECK_INTERVAL_SECONDS", _CHECK_INTERVAL),
+            patch("deerflow.skills.curator.maybe_run_curator", fake_curator),
+            patch("asyncio.sleep", fake_sleep),
+        ):
+            task = asyncio.create_task(mod._curator_scheduler_loop())
+            try:
+                await task
+            except asyncio.CancelledError:
+                pass
+
+    asyncio.run(run())
+    assert curator_call_count >= 1, (
+        f"maybe_run_curator should have been called at least once, got {curator_call_count}"
+    )
+
+
+def test_scheduler_skips_when_lock_unavailable():
+    """When another worker holds the lock the loop must exit without doing any work."""
+    mod = _gateway_module()
+    curator_called = False
+
+    async def fake_curator():
+        nonlocal curator_called
+        curator_called = True
+
+    async def run():
+        with (
+            patch.object(mod, "_acquire_singleton_lock", return_value=None),
+            patch("deerflow.skills.curator.maybe_run_curator", fake_curator),
+        ):
+            await mod._curator_scheduler_loop()
+
+    asyncio.run(run())
+    assert not curator_called, "curator must not run when lock is not acquired"