diff --git a/asknews_sdk/api/chat.py b/asknews_sdk/api/chat.py
index b151bc0..c360c15 100644
--- a/asknews_sdk/api/chat.py
+++ b/asknews_sdk/api/chat.py
@@ -71,7 +71,9 @@
     "gemini-2.5-flash",
     "o3",
     "gpt-5.6-sol",
+    "gpt-6-sol",
     "claude-opus-4-8",
+    "claude-opus-5-5",
     "gpt-5.6-terra",
 ]
 
diff --git a/tests/api/test_chat_model_types.py b/tests/api/test_chat_model_types.py
index 62cd6b3..7e9e1b3 100644
--- a/tests/api/test_chat_model_types.py
+++ b/tests/api/test_chat_model_types.py
@@ -7,10 +7,12 @@
 
 from asknews_sdk.api.chat import AsyncChatAPI, ChatAPI, ChatModel, DeepNewsModel
 from asknews_sdk.dto import alert as alert_dto
+from asknews_sdk.dto.deepnews import CreateDeepNewsRequest
 
 
 GPT_6_ASTRA = "gpt-6-astra"
 CLAUDE_FABLE_MODELS = ("claude-fable-5", "claude-fable-5-1")
+ADVANCED_DEEPNEWS_MODELS = ("claude-opus-5-5", "gpt-6-sol")
 
 
 def test_gpt_6_astra_is_a_direct_deepnews_model_only():
@@ -41,6 +43,24 @@ def test_gpt_6_astra_is_absent_from_alert_model_contracts():
             assert GPT_6_ASTRA not in json.dumps(model.model_json_schema()), name
 
 
+@pytest.mark.parametrize("model", ADVANCED_DEEPNEWS_MODELS)
+@pytest.mark.parametrize("api_type", [ChatAPI, AsyncChatAPI])
+def test_advanced_models_are_scoped_to_deepnews_and_preserve_alert_contracts(model, api_type):
+    assert model in get_args(DeepNewsModel)
+    assert model in get_args(get_type_hints(api_type.get_deep_news)["model"])
+    assert model not in get_args(ChatModel)
+    assert model not in get_args(alert_dto.DeepNewsModel)
+    assert model not in get_args(alert_dto.CheckAlertModel)
+    assert model not in get_args(alert_dto.AlertReportModel)
+
+
+@pytest.mark.parametrize("model", ADVANCED_DEEPNEWS_MODELS)
+def test_advanced_deepnews_models_serialize_in_requests(model):
+    request = CreateDeepNewsRequest(messages=[{"role": "user", "content": "query"}], model=model)
+
+    assert request.model_dump(mode="json")["model"] == model
+
+
 @pytest.mark.parametrize("model", CLAUDE_FABLE_MODELS)
 def test_claude_fable_models_match_deepnews_and_alert_report_contracts(model):
     assert model in get_args(DeepNewsModel)