fix(agents): reject empty agents list in runner helpers

src/rai_core/rai/agents/runner.py

@@ -37,6 +37,8 @@ def wait_for_shutdown(agents: List[BaseAgent]):
     an interrupt signal (SIGINT, e.g., Ctrl+C) or SIGTERM. It installs signal handlers to
     capture these events and invokes the agent's ``stop()`` method as part of the shutdown process.
     """
+    if not isinstance(agents, list) or len(agents) == 0:
+        raise ValueError("agents must be a non-empty list of BaseAgent instances")
     shutdown_event = Event()
 
     def signal_handler(signum, frame):
@@ -58,6 +60,8 @@ def run_agents(agents: List[BaseAgent]):
     Args:
         agents: List of agent instances
     """
+    if not isinstance(agents, list) or len(agents) == 0:
+        raise ValueError("agents must be a non-empty list of BaseAgent instances")
     logger.info(
         "run_agents is an experimental function. \
                    If you believe that your agents are not running properly, \
@@ -84,6 +88,8 @@ def __init__(self, agents: List[BaseAgent]):
         agents : List[BaseAgent]
             List of agent instances to be managed by the runner.
         """
+        if not isinstance(agents, list) or len(agents) == 0:
+            raise ValueError("agents must be a non-empty list of BaseAgent instances")
         self.agents = agents
         self.logger = logging.getLogger(__name__)
 

tests/agents/test_agent_runner_empty.py

@@ -0,0 +1,30 @@
+# 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.
+
+import pytest
+from rai.agents.runner import AgentRunner, run_agents, wait_for_shutdown
+
+
+@pytest.mark.parametrize(
+    "fn",
+    [
+        lambda: run_agents([]),
+        lambda: wait_for_shutdown([]),
+        lambda: AgentRunner([]),
+        lambda: run_agents(None),  # type: ignore[arg-type]
+    ],
+)
+def test_agent_helpers_reject_empty_agents(fn):
+    with pytest.raises(ValueError, match="agents must be a non-empty list"):
+        fn()