diff --git a/src/app_runtime/control/http_channel.py b/src/app_runtime/control/http_channel.py
index 9d5a374..1073279 100644
--- a/src/app_runtime/control/http_channel.py
+++ b/src/app_runtime/control/http_channel.py
@@ -44,10 +44,14 @@ class HttpControlChannel(ControlChannel):
         callback = callbacks.get(action)
         if callback is None:
             return JSONResponse(content={"status": "error", "detail": f"unsupported action: {action}"}, status_code=404)
+        action_timeout = max(float(self._timeout), 10.0) if action in {"start", "stop"} else float(self._timeout)
         try:
-            detail = await asyncio.wait_for(callback(), timeout=float(self._timeout))
+            detail = await asyncio.wait_for(callback(), timeout=action_timeout)
         except asyncio.TimeoutError:
-            return JSONResponse(content={"status": "error", "detail": f"{action} handler timeout"}, status_code=504)
+            return JSONResponse(
+                content={"status": "accepted", "detail": f"{action} operation is still in progress"},
+                status_code=202,
+            )
         except Exception as exc:
             return JSONResponse(content={"status": "error", "detail": str(exc)}, status_code=500)
         return JSONResponse(content={"status": "ok", "detail": detail or f"{action} action accepted"}, status_code=200)
diff --git a/src/app_runtime/core/runtime.py b/src/app_runtime/core/runtime.py
index 9ccf539..521ec1f 100644
--- a/src/app_runtime/core/runtime.py
+++ b/src/app_runtime/core/runtime.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from time import monotonic, sleep
+
 from app_runtime.config.providers import FileConfigProvider
 from app_runtime.contracts.application import ApplicationModule
 from app_runtime.control.service import ControlPlaneService
@@ -14,6 +16,9 @@ from app_runtime.workers.supervisor import WorkerSupervisor
 
 
 class RuntimeManager:
+    ACTION_TIMEOUT_SECONDS = 10.0
+    ACTION_POLL_INTERVAL_SECONDS = 0.05
+
     def __init__(
         self,
         configuration: ConfigurationManager | None = None,
@@ -65,16 +70,11 @@ class RuntimeManager:
         if not self._started:
             return
         self._state = LifecycleState.STOPPING
-        try:
-            self.workers.stop(timeout=timeout, force=force)
-        except TimeoutError:
-            # Do not leave runtime in STOPPING forever for control-plane callers.
-            self.workers.stop(force=True)
-        finally:
-            if stop_control_plane:
-                self.control_plane.stop()
-            self._started = False
-            self._state = LifecycleState.STOPPED
+        self.workers.stop(timeout=timeout, force=force)
+        if stop_control_plane:
+            self.control_plane.stop()
+        self._started = False
+        self._state = LifecycleState.STOPPED
 
     def status(self) -> dict[str, object]:
         self._refresh_state()
@@ -87,19 +87,35 @@ class RuntimeManager:
     async def health_status(self) -> HealthPayload:
         return self.current_health()
 
-    async def start_runtime(self) -> str:
+    async def start_runtime(self) -> dict[str, object] | str:
+        self._refresh_state()
         if self._started:
             return "runtime already running"
         if self._state == LifecycleState.STOPPING:
-            return "runtime is stopping"
-        self.start(start_control_plane=False)
-        return "runtime started"
+            return self._action_detail("runtime stop is still in progress", timed_out=True)
 
-    async def stop_runtime(self) -> str:
+        self.start(start_control_plane=False)
+        started = self._wait_for_state({LifecycleState.IDLE, LifecycleState.BUSY}, timeout=self.ACTION_TIMEOUT_SECONDS)
+        if started:
+            return self._action_detail("runtime started", timed_out=False)
+        return self._action_detail("runtime start is still in progress", timed_out=True)
+
+    async def stop_runtime(self) -> dict[str, object] | str:
+        self._refresh_state()
         if not self._started:
+            if self._state == LifecycleState.STOPPING:
+                return self._action_detail("runtime stop is still in progress", timed_out=True)
             return "runtime already stopped"
-        self.stop(timeout=0.0, stop_control_plane=False)
-        return "runtime stopped"
+
+        self._state = LifecycleState.STOPPING
+        try:
+            self.workers.stop(timeout=self.ACTION_TIMEOUT_SECONDS, force=False)
+        except TimeoutError:
+            return self._action_detail("runtime stop is still in progress", timed_out=True)
+
+        self._started = False
+        self._state = LifecycleState.STOPPED
+        return self._action_detail("runtime stopped", timed_out=False)
 
     async def runtime_status(self) -> str:
         self._refresh_state()
@@ -128,6 +144,36 @@ class RuntimeManager:
         self._workers_registered = True
 
     def _refresh_state(self) -> None:
-        if not self._started or self._state == LifecycleState.STOPPING:
+        lifecycle = self.workers.lifecycle_state()
+
+        if self._state == LifecycleState.STOPPING:
+            if lifecycle == LifecycleState.STOPPED:
+                self._started = False
+                self._state = LifecycleState.STOPPED
             return
-        self._state = self.workers.lifecycle_state()
+
+        if not self._started:
+            if lifecycle == LifecycleState.STOPPED:
+                self._state = LifecycleState.STOPPED
+            return
+
+        self._state = lifecycle
+
+    def _wait_for_state(self, target_states: set[LifecycleState], *, timeout: float) -> bool:
+        deadline = monotonic() + timeout
+        while monotonic() < deadline:
+            self._refresh_state()
+            if self._state in target_states:
+                return True
+            sleep(self.ACTION_POLL_INTERVAL_SECONDS)
+        self._refresh_state()
+        return self._state in target_states
+
+    def _action_detail(self, message: str, *, timed_out: bool) -> dict[str, object]:
+        self._refresh_state()
+        return {
+            "message": message,
+            "state": self._state.value,
+            "timed_out": timed_out,
+            "workers": self.workers.snapshot(),
+        }