fix(dashscope): forward reasoning_effort to the provider

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/llms/dashscope/chat/transformation.py

@@ -12,6 +12,12 @@ from ...openai.chat.gpt_transformation import OpenAIGPTConfig
 
 
 class DashScopeChatConfig(OpenAIGPTConfig):
+    def get_supported_openai_params(self, model: str) -> list:  # mutable-ok: base class contract returns a list
+        return [  # mutable-ok: base class contract returns a list
+            *super().get_supported_openai_params(model=model),
+            "reasoning_effort",
+        ]
+
     def remove_cache_control_flag_from_messages_and_tools(
         self,
         model: str,

tests/test_litellm/llms/dashscope/test_dashscope_chat_transformation.py

@@ -169,6 +169,21 @@ class TestDashScopeConfig:
 
         assert transformed_messages[0].get("cache_control") == {"type": "ephemeral"}
 
+    @pytest.mark.parametrize("reasoning_effort", ["none", "minimal", "low", "high"])
+    def test_dashscope_forwards_reasoning_effort(self, reasoning_effort: str):
+        """DashScope supports reasoning_effort, so it must reach the provider instead of being dropped."""
+        assert "reasoning_effort" in DashScopeChatConfig().get_supported_openai_params(
+            model="qwen3.7-plus"
+        )
+
+        optional_params = litellm.get_optional_params(
+            model="qwen3.7-plus",
+            custom_llm_provider="dashscope",
+            reasoning_effort=reasoning_effort,
+        )
+
+        assert optional_params["reasoning_effort"] == reasoning_effort
+
     def test_dashscope_preserves_cache_control_in_tools(self):
         """DashScope should NOT strip cache_control from tools."""
         config = DashScopeChatConfig()