fix(object_detector): resolve the detector model from utils config

artemis/agents/object_detector/object_detector.py

@@ -124,8 +124,11 @@ async def _run_object_detection(
     queries = queries or []
     templates = templates or ["Point to the following objects: {labels_str}"]
     try:
-        llm = get_llm(ctx, name="object_detector")
-    except Exception:
+        llm = get_llm(ctx, name="object_detector", is_utils=True)
+    except Exception as e:
+        logger.warning(
+            f"Object detector model unavailable ({e}); falling back to the operator model."
+        )
         llm = get_llm(ctx, name="operator")
 
     raw_timeout = getattr(getattr(ctx, "llm_config", None), "timeout", None)

tests/unit/agents/test_object_detector_model_resolution.py

@@ -0,0 +1,60 @@
+# Copyright 2026 Google LLC
+#
+# 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.
+
+"""The object detector must resolve its model from the ``utils.object_detector`` config."""
+
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from artemis.agents.object_detector import object_detector as od
+
+_MODULE = "artemis.agents.object_detector.object_detector"
+
+
+@pytest.mark.asyncio
+async def test_detector_uses_the_utils_object_detector_model():
+    detector_llm = MagicMock(name="object_detector_llm")
+    get_llm = MagicMock(return_value=detector_llm)
+    detect = AsyncMock(return_value=[])
+
+    with patch(f"{_MODULE}.get_llm", get_llm), patch(f"{_MODULE}._detect_single_label", detect):
+        await od._run_object_detection(MagicMock(), image_bytes=b"img", queries=["OK button"])
+
+    get_llm.assert_called_once()
+    assert get_llm.call_args.kwargs.get("name") == "object_detector"
+    assert get_llm.call_args.kwargs.get("is_utils") is True
+    assert detect.call_args.args[0] is detector_llm
+
+
+@pytest.mark.asyncio
+async def test_detector_falls_back_to_the_operator_model_with_a_warning():
+    operator_llm = MagicMock(name="operator_llm")
+
+    def fake_get_llm(ctx, *, name, **kwargs):
+        if name == "object_detector":
+            raise ValueError("detector model not configured")
+        return operator_llm
+
+    detect = AsyncMock(return_value=[])
+    with (
+        patch(f"{_MODULE}.get_llm", side_effect=fake_get_llm),
+        patch(f"{_MODULE}._detect_single_label", detect),
+        patch(f"{_MODULE}.logger") as logger,
+    ):
+        await od._run_object_detection(MagicMock(), image_bytes=b"img", queries=["OK button"])
+
+    assert detect.call_args.args[0] is operator_llm
+    logger.warning.assert_called_once()
+    assert "operator" in logger.warning.call_args.args[0]