fix(dashscope): address PR review feedback for Responses API config

- Add supports_native_websocket() returning False (DashScope has no native WS)
- Remove metadata from _SUPPORTED_OPTIONAL_PARAMS (was contradictory)
- Add DashScopeResponsesAPIConfig to TYPE_CHECKING block in __init__.py
- Fix get_complete_url fallback to use /responses for custom proxy URLs

litellm/__init__.py

@@ -1632,6 +1632,9 @@ if TYPE_CHECKING:
     from .llms.volcengine.responses.transformation import (
         VolcEngineResponsesAPIConfig as VolcEngineResponsesAPIConfig,
     )
+    from .llms.dashscope.responses.transformation import (
+        DashScopeResponsesAPIConfig as DashScopeResponsesAPIConfig,
+    )
     from .llms.manus.responses.transformation import (
         ManusResponsesAPIConfig as ManusResponsesAPIConfig,
     )

litellm/llms/dashscope/responses/transformation.py

@@ -23,7 +23,6 @@ _DEFAULT_API_BASE = "https://dashscope.aliyuncs.com/compatible-mode/v1"
 _SUPPORTED_OPTIONAL_PARAMS: List[str] = [
     "instructions",
     "max_output_tokens",
-    "metadata",
     "previous_response_id",
     "reasoning",
     "store",
@@ -48,13 +47,13 @@ class DashScopeResponsesAPIConfig(OpenAIResponsesAPIConfig):
     def custom_llm_provider(self) -> LlmProviders:
         return LlmProviders.DASHSCOPE
 
+    def supports_native_websocket(self) -> bool:
+        """DashScope compatible-mode does not expose a native WebSocket endpoint."""
+        return False
+
     def get_supported_openai_params(self, model: str) -> list:
         """Return the parameter whitelist for DashScope Responses API."""
-        supported = ["input", "model"] + list(_SUPPORTED_OPTIONAL_PARAMS)
-        # metadata is LiteLLM-internal; advertise all others
-        if "metadata" in supported:
-            supported.remove("metadata")
-        return supported
+        return ["input", "model"] + list(_SUPPORTED_OPTIONAL_PARAMS)
 
     def map_openai_params(
         self,
@@ -125,7 +124,7 @@ class DashScopeResponsesAPIConfig(OpenAIResponsesAPIConfig):
             return f"{base_url}/responses"
         if base_url.endswith("/compatible-mode/v1"):
             return f"{base_url}/responses"
-        return f"{base_url}/compatible-mode/v1/responses"
+        return f"{base_url}/responses"
 
     def get_error_class(
         self,

tests/test_litellm/llms/dashscope/responses/test_dashscope_responses_transformation.py

@@ -63,7 +63,7 @@ class TestDashScopeResponsesAPITransformation:
         url = config.get_complete_url(
             api_base="https://custom.example.com", litellm_params={}
         )
-        assert url == "https://custom.example.com/compatible-mode/v1/responses"
+        assert url == "https://custom.example.com/responses"
 
     @pytest.mark.parametrize(
         "litellm_params, expected_key",