diff --git a/solstone/think/cortex.py b/solstone/think/cortex.py
index 027ca5bca..73351e9bb 100644
--- a/solstone/think/cortex.py
+++ b/solstone/think/cortex.py
@@ -258,16 +258,6 @@ class CortexService:
             name="cortex-status",
             daemon=True,
         ).start()
-
-    def _should_request_brain_refresh(self) -> bool:
-        try:
-            inspection = inspect_brain_state(datetime.now(timezone.utc))
-        except Exception:
-            return True
-        projection = inspection["projection"]
-        if projection["aggregate_state"] in {"checking", "ready"}:
-            return False
-        return not projection["runtime_transition_in_progress"]
         self._spawn_worker = threading.Thread(
             target=self._run_spawn_worker,
             name="cortex-spawn-worker",
@@ -293,6 +283,16 @@ class CortexService:
                 self.logger.info("Shutdown requested, will exit when idle")
                 self.shutdown_requested.set()
 
+    def _should_request_brain_refresh(self) -> bool:
+        try:
+            inspection = inspect_brain_state(datetime.now(timezone.utc))
+        except Exception:
+            return True
+        projection = inspection["projection"]
+        if projection["aggregate_state"] in {"checking", "ready"}:
+            return False
+        return not projection["runtime_transition_in_progress"]
+
     def _handle_callosum_message(self, message: Dict[str, Any]) -> None:
         """Handle incoming Callosum messages (callback)."""
         # Filter for cortex tract and request event
diff --git a/tests/test_cortex.py b/tests/test_cortex.py
index f1824d495..bfd3659ca 100644
--- a/tests/test_cortex.py
+++ b/tests/test_cortex.py
@@ -127,6 +127,54 @@ def test_cortex_service_initialization(cortex_service, mock_journal):
     assert cortex_service.talents_dir.exists()
 
 
+def test_start_starts_spawn_worker_and_stays_resident(cortex_service, monkeypatch):
+    from solstone.think import cortex
+
+    fake_callosum = MagicMock()
+    cortex_service.callosum = fake_callosum
+    monkeypatch.setattr(cortex_service, "_should_request_brain_refresh", lambda: False)
+    monkeypatch.setattr(cortex_service, "_emit_periodic_status", lambda: None)
+
+    resident_loop_entered = threading.Event()
+    returned = threading.Event()
+    errors: list[BaseException] = []
+    real_sleep = time.sleep
+
+    def short_sleep(_seconds):
+        resident_loop_entered.set()
+        real_sleep(0.01)
+
+    monkeypatch.setattr(cortex.time, "sleep", short_sleep)
+
+    def run_start():
+        try:
+            cortex_service.start()
+        except BaseException as exc:  # pragma: no cover - surfaced below
+            errors.append(exc)
+        finally:
+            returned.set()
+
+    service_thread = threading.Thread(target=run_start, daemon=True)
+    service_thread.start()
+    try:
+        assert resident_loop_entered.wait(1)
+        assert fake_callosum.start.called
+        assert cortex_service._spawn_worker is not None
+        assert cortex_service._spawn_worker.is_alive()
+        assert service_thread.is_alive()
+        assert not returned.is_set()
+
+        cortex_service.shutdown_requested.set()
+        service_thread.join(timeout=1)
+        assert returned.is_set()
+        assert errors == []
+    finally:
+        cortex_service.stop_event.set()
+        if cortex_service._spawn_worker is not None:
+            cortex_service._spawn_worker.join(timeout=1)
+        service_thread.join(timeout=1)
+
+
 def test_handle_request_dedups_existing_active_file(
     cortex_service, mock_journal, monkeypatch
 ):