diff --git a/src/rai_core/rai/communication/ros2/context.py b/src/rai_core/rai/communication/ros2/context.py
index 9d12fa5d9..21675bbcc 100644
--- a/src/rai_core/rai/communication/ros2/context.py
+++ b/src/rai_core/rai/communication/ros2/context.py
@@ -154,7 +154,11 @@ def __init__(
         period_sec: float = 0.5,
         setters: Optional[List[Callable]] = None,
     ) -> None:
-        self.period_sec = period_sec
+        if not isinstance(period_sec, (int, float)) or isinstance(period_sec, bool):
+            raise ValueError("period_sec must be a positive number")
+        if not (period_sec > 0) or period_sec != period_sec:  # NaN check
+            raise ValueError("period_sec must be positive")
+        self.period_sec = float(period_sec)
         self.node = node
 
         self.topics_and_types: Dict[str, str] = dict()
diff --git a/tests/communication_offline/test_node_discovery_period.py b/tests/communication_offline/test_node_discovery_period.py
new file mode 100644
index 000000000..03f661d05
--- /dev/null
+++ b/tests/communication_offline/test_node_discovery_period.py
@@ -0,0 +1,23 @@
+# Copyright (C) 2026 Robotec.AI
+from unittest.mock import MagicMock
+
+import pytest
+
+from rai.communication.ros2.context import NodeDiscovery
+
+
+def test_node_discovery_rejects_non_positive_period_sec():
+    node = MagicMock()
+    with pytest.raises(ValueError, match="period_sec"):
+        NodeDiscovery(node, period_sec=0)
+    with pytest.raises(ValueError, match="period_sec"):
+        NodeDiscovery(node, period_sec=-1.0)
+    with pytest.raises(ValueError, match="period_sec"):
+        NodeDiscovery(node, period_sec=float("nan"))
+
+
+def test_node_discovery_accepts_positive_period_sec():
+    node = MagicMock()
+    d = NodeDiscovery(node, period_sec=0.25)
+    assert d.period_sec == 0.25
+    node.create_timer.assert_called()