diff --git a/emper/strategies/AbstractWorkStealingScheduler.cpp b/emper/strategies/AbstractWorkStealingScheduler.cpp
index fe5f39400dcce403385986bda34e5166700a1028..6045e06df12f4cd9f1f08e58bd178885e05d3702 100644
--- a/emper/strategies/AbstractWorkStealingScheduler.cpp
+++ b/emper/strategies/AbstractWorkStealingScheduler.cpp
@@ -292,6 +292,8 @@ auto AbstractWorkStealingScheduler::nextFiberResultFromMpscQueueOrWorkStealing()
 }
 
 auto AbstractWorkStealingScheduler::pushBottom(AbstractFiber& fiber) -> bool {
+	emper::assertInRuntime();
+
 	auto pushed = queue.pushBottom(&fiber);
 	if (pushed) [[likely]] {
 		onNewWork<CallerEnvironment::EMPER>(emper::FiberHint{emper::FiberSource::local});