diff --git a/src/utils/responses.py b/src/utils/responses.py
index bdced0f71..9fd9ceef9 100644
--- a/src/utils/responses.py
+++ b/src/utils/responses.py
@@ -842,6 +842,16 @@ def _resolve_source_for_result(
 
     if len(vector_store_ids) > 1:
         attributes = getattr(result, "attributes", {}) or {}
+
+        # Primary: read index name embedded directly by rag-content.
+        # This value is already the user-facing rag_id, not a vector_db_id,
+        # so no mapping is needed.
+        attr_source: Optional[str] = attributes.get("source")
+        if attr_source:
+            return attr_source
+
+        # Fallback: if llama-stack ever populates vector_store_id in results,
+        # use it with the rag_id_mapping.
         attr_store_id: Optional[str] = attributes.get("vector_store_id")
         if attr_store_id:
             return rag_id_mapping.get(attr_store_id, attr_store_id)
diff --git a/tests/unit/utils/test_responses.py b/tests/unit/utils/test_responses.py
index 54ae158aa..f9b5f3a9e 100644
--- a/tests/unit/utils/test_responses.py
+++ b/tests/unit/utils/test_responses.py
@@ -2044,6 +2044,69 @@ def test_multiple_stores_attribute_not_in_mapping(
         )
         assert source == "vs-unknown"
 
+    def test_multiple_stores_source_attribute_fallback(
+        self, mocker: MockerFixture
+    ) -> None:
+        """Test resolution falls back to source attribute when no vector_store_id."""
+        mock_result = mocker.Mock()
+        mock_result.filename = "file-abc123"
+        mock_result.attributes = {"source": "ocp-documentation"}
+
+        source = _resolve_source_for_result(
+            mock_result,
+            ["vs-001", "vs-002"],
+            {"vs-001": "ocp-4.18-docs"},
+        )
+        assert source == "ocp-documentation"
+
+    def test_multiple_stores_source_attribute_ignores_mapping(
+        self, mocker: MockerFixture
+    ) -> None:
+        """Test source attribute is returned directly without rag_id_mapping lookup."""
+        mock_result = mocker.Mock()
+        mock_result.filename = "file-abc123"
+        mock_result.attributes = {"source": "custom-index"}
+
+        source = _resolve_source_for_result(
+            mock_result,
+            ["vs-001", "vs-002"],
+            {"custom-index": "should-not-be-used"},
+        )
+        assert source == "custom-index"
+
+    def test_multiple_stores_source_preferred_over_vector_store_id(
+        self, mocker: MockerFixture
+    ) -> None:
+        """Test source attribute takes precedence over vector_store_id."""
+        mock_result = mocker.Mock()
+        mock_result.filename = "file-abc123"
+        mock_result.attributes = {
+            "vector_store_id": "vs-002",
+            "source": "ocp-documentation",
+        }
+
+        source = _resolve_source_for_result(
+            mock_result,
+            ["vs-001", "vs-002"],
+            {"vs-002": "rhel-9-docs"},
+        )
+        assert source == "ocp-documentation"
+
+    def test_multiple_stores_no_vector_store_id_no_source(
+        self, mocker: MockerFixture
+    ) -> None:
+        """Test resolution returns None when neither vector_store_id nor source present."""
+        mock_result = mocker.Mock()
+        mock_result.filename = "file-abc123"
+        mock_result.attributes = {"title": "some doc"}
+
+        source = _resolve_source_for_result(
+            mock_result,
+            ["vs-001", "vs-002"],
+            {"vs-001": "ocp-docs"},
+        )
+        assert source is None
+
 
 class TestBuildChunkAttributes:
     """Tests for _build_chunk_attributes function."""