Support Deepseek 3.2 with Reasoning (#17384)

* Add openrouter/deepseek/deepseek-v3.2

* Added deepseek-provided v3.2

* Allow reasoning effort param for openrouter models that support it

* Added tests

litellm/llms/openrouter/chat/transformation.py

@@ -10,6 +10,7 @@ from enum import Enum
 from typing import Any, AsyncIterator, Iterator, List, Optional, Tuple, Union, cast
 
 import httpx
+import litellm
 
 from litellm.llms.base_llm.base_model_iterator import BaseModelResponseIterator
 from litellm.llms.base_llm.chat.transformation import BaseLLMException
@@ -28,6 +29,20 @@ class CacheControlSupportedModels(str, Enum):
 
 
 class OpenrouterConfig(OpenAIGPTConfig):
+    def get_supported_openai_params(self, model: str) -> list:
+        """
+        Allow reasoning parameters for models flagged as reasoning-capable.
+        """
+        supported_params = super().get_supported_openai_params(model=model)
+        try:
+            if litellm.supports_reasoning(
+                model=model, custom_llm_provider="openrouter"
+            ) or litellm.supports_reasoning(model=model):
+                supported_params.append("reasoning_effort")
+        except Exception:
+            pass
+        return list(dict.fromkeys(supported_params))
+
     def map_openai_params(
         self,
         non_default_params: dict,

model_prices_and_context_window.json

@@ -9629,6 +9629,21 @@
         "supports_prompt_caching": true,
         "supports_tool_choice": true
     },
+    "deepseek/deepseek-v3.2": {
+        "input_cost_per_token": 2.8e-07,
+        "input_cost_per_token_cache_hit": 2.8e-08,
+        "litellm_provider": "deepseek",
+        "max_input_tokens": 163840,
+        "max_output_tokens": 163840,
+        "max_tokens": 8192,
+        "mode": "chat",
+        "output_cost_per_token": 4e-07,
+        "supports_assistant_prefill": true,
+        "supports_function_calling": true,
+        "supports_prompt_caching": true,
+        "supports_reasoning": true,
+        "supports_tool_choice": true
+    },
     "deepseek.v3-v1:0": {
         "input_cost_per_token": 5.8e-07,
         "litellm_provider": "bedrock_converse",
@@ -20565,6 +20580,21 @@
         "supports_reasoning": true,
         "supports_tool_choice": true
     },
+    "openrouter/deepseek/deepseek-v3.2": {
+        "input_cost_per_token": 2.8e-07,
+        "input_cost_per_token_cache_hit": 2.8e-08,
+        "litellm_provider": "openrouter",
+        "max_input_tokens": 163840,
+        "max_output_tokens": 163840,
+        "max_tokens": 8192,
+        "mode": "chat",
+        "output_cost_per_token": 4e-07,
+        "supports_assistant_prefill": true,
+        "supports_function_calling": true,
+        "supports_prompt_caching": true,
+        "supports_reasoning": true,
+        "supports_tool_choice": true
+    },
     "openrouter/deepseek/deepseek-v3.2-exp": {
         "input_cost_per_token": 2e-07,
         "input_cost_per_token_cache_hit": 2e-08,

tests/test_litellm/llms/openrouter/chat/test_openrouter_chat_transformation.py

@@ -489,3 +489,30 @@ def test_openrouter_cost_tracking_streaming():
     # Verify cost field is preserved in the Usage object - this is the key data for cost tracking
     # The chunk_parser converts the dict to a Usage Pydantic model which includes the cost field
     assert result2.usage.cost == 0.0001
+
+
+def test_openrouter_reasoning_models_allow_reasoning_effort_param():
+    """
+    OpenRouter reasoning-capable models should accept the reasoning_effort param.
+    """
+    config = OpenrouterConfig()
+
+    supported_params = config.get_supported_openai_params(
+        model="openrouter/deepseek/deepseek-v3.2"
+    )
+
+    assert "reasoning_effort" in supported_params
+    assert supported_params.count("reasoning_effort") == 1
+
+
+def test_openrouter_non_reasoning_models_do_not_add_reasoning_effort():
+    """
+    Models without reasoning support should not gain reasoning-specific params.
+    """
+    config = OpenrouterConfig()
+
+    supported_params = config.get_supported_openai_params(
+        model="openrouter/anthropic/claude-3-5-haiku"
+    )
+
+    assert "reasoning_effort" not in supported_params