diff --git a/src/rai_core/rai/messages/artifacts.py b/src/rai_core/rai/messages/artifacts.py
index 870174344..d8711dfce 100644
--- a/src/rai_core/rai/messages/artifacts.py
+++ b/src/rai_core/rai/messages/artifacts.py
@@ -26,6 +26,10 @@ def store_artifacts(
     tool_call_id: str, artifacts: List[Any], db_path="artifact_database.pkl"
 ):
     # TODO(boczekbartek): refactor
+    if not isinstance(tool_call_id, str) or not tool_call_id.strip():
+        raise ValueError(
+            f"tool_call_id must be a non-empty string, got {tool_call_id!r}"
+        )
     path = Path(db_path)
     if not path.is_file():
         artifact_database: dict = {}
@@ -45,6 +49,10 @@ def get_stored_artifacts(
     tool_call_id: str, db_path="artifact_database.pkl"
 ) -> List[Any]:
     # TODO(boczekbartek): refactor
+    if not isinstance(tool_call_id, str) or not tool_call_id.strip():
+        raise ValueError(
+            f"tool_call_id must be a non-empty string, got {tool_call_id!r}"
+        )
     db_path = Path(db_path)
     if not db_path.is_file():
         return []
diff --git a/tests/communication/__init__.py b/tests/communication/__init__.py
index e69de29bb..97ceef6f0 100644
--- a/tests/communication/__init__.py
+++ b/tests/communication/__init__.py
@@ -0,0 +1,13 @@
+# Copyright (C) 2025 Robotec.AI
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
diff --git a/tests/communication/ros2/test_ros2_async.py b/tests/communication/ros2/test_ros2_async.py
index 25ec290c3..bd50055c9 100644
--- a/tests/communication/ros2/test_ros2_async.py
+++ b/tests/communication/ros2/test_ros2_async.py
@@ -125,10 +125,10 @@ def cancel_future():
 
 # Edge case timeout tests
 def test_get_future_result_zero_timeout():
-    """Test with zero timeout."""
+    """Test that a zero timeout is rejected as non-positive."""
     future = Future()
-    result = get_future_result(future, timeout_sec=0.0)
-    assert result is None
+    with pytest.raises(ValueError, match="timeout_sec must be positive"):
+        get_future_result(future, timeout_sec=0.0)
 
 
 def test_get_future_result_very_short_timeout():
diff --git a/tests/messages/test_artifacts_db_path.py b/tests/messages/test_artifacts_db_path.py
index bb11eb4f0..c80d150fa 100644
--- a/tests/messages/test_artifacts_db_path.py
+++ b/tests/messages/test_artifacts_db_path.py
@@ -32,3 +32,14 @@ def test_store_artifacts_creates_file_at_path(tmp_path: Path):
     db.parent.mkdir(parents=True)
     store_artifacts("x", [1], db_path=str(db))
     assert get_stored_artifacts("x", db_path=str(db)) == [1]
+
+
+def test_store_artifacts_rejects_empty_tool_call_id(tmp_path: Path):
+    import pytest
+
+    db = tmp_path / "db.pkl"
+    for bad in ("", "   ", None, 123):
+        with pytest.raises(ValueError, match="tool_call_id must be a non-empty string"):
+            store_artifacts(bad, ["a"], db_path=str(db))  # type: ignore[arg-type]
+        with pytest.raises(ValueError, match="tool_call_id must be a non-empty string"):
+            get_stored_artifacts(bad, db_path=str(db))  # type: ignore[arg-type]