Merge pull request #41509 from BerriAI/litellm_mantle_gpt5_verbosity

fix(bedrock_mantle): accept and forward verbosity on gpt-5.x chat completions

litellm/completion_extras/litellm_responses_transformation/transformation.py

@@ -502,7 +502,12 @@ class LiteLLMResponsesTransformationHandler(CompletionTransformationBridge):
             elif key == "response_format":
                 text_format = self._transform_response_format_to_text_format(value)
                 if text_format:
-                    responses_api_request["text"] = text_format
+                    responses_api_request["text"] = self._merge_text(responses_api_request, text_format)
+            elif key == "verbosity":
+                responses_api_request["text"] = self._merge_text(
+                    responses_api_request,
+                    MappingProxyType({"verbosity": value}),  # pyright: ignore[reportUnknownArgumentType]  # untyped value
+                )
             elif key == "tool_choice":
                 responses_api_request["tool_choice"] = self._normalize_tool_choice_for_responses_api(value)
             elif key == "stream_options":
@@ -518,6 +523,19 @@ class LiteLLMResponsesTransformationHandler(CompletionTransformationBridge):
             elif key == "web_search_options":
                 self._add_web_search_tool(responses_api_request, value)
 
+    @staticmethod
+    def _merge_text(
+        responses_api_request: "ResponsesAPIOptionalRequestParams", update: Mapping[str, object]
+    ) -> "ResponseText":
+        existing: Final = cast(  # cast-ok: text field is a ResponseText | dict[str, Any] | None union
+            "dict[str, object]",
+            dict(responses_api_request).get("text") or {},  # mutable-ok: one-shot merge seed
+        )
+        return cast(  # cast-ok: merged mapping is a valid ResponseText shape
+            "ResponseText",
+            {**existing, **update},  # mutable-ok: one-shot merged payload
+        )
+
     def _build_sanitized_litellm_params(self, litellm_params: dict) -> dict[str, object]:
         """Build sanitized litellm_params with merged metadata."""
         responses_optional_param_keys: Final = set(ResponsesAPIOptionalRequestParams.__annotations__.keys())

litellm/llms/bedrock_mantle/chat/transformation.py

@@ -22,6 +22,7 @@ from litellm.llms.bedrock_mantle.common_utils import (
     BEDROCK_MANTLE_DEFAULT_REGION,
     BedrockMantleAuthMixin,
 )
+from litellm.llms.openai.chat.gpt_5_transformation import is_gpt_reasoning_series_name
 from litellm.secret_managers.main import get_secret_str
 from litellm.types.llms.openai import AllMessageValues
 from litellm.types.router import GenericLiteLLMParams
@@ -108,13 +109,22 @@ class BedrockMantleChatConfig(BedrockMantleAuthMixin, OpenAILikeChatConfig):
 
     def get_supported_openai_params(self, model: str) -> list:
         base_params: Final = super().get_supported_openai_params(model)
+        extra_params: Final = tuple(
+            param
+            for param, supported in (
+                ("verbosity", is_gpt_reasoning_series_name(model)),
+                ("reasoning_effort", self._supports_reasoning(model)),
+            )
+            if supported and param not in base_params
+        )
+        return [*base_params, *extra_params]  # mutable-ok: fresh list required by the inherited signature
+
+    def _supports_reasoning(self, model: str) -> bool:
         try:
-            if litellm.supports_reasoning(model=model, custom_llm_provider=self.custom_llm_provider):
-                if "reasoning_effort" not in base_params:
-                    base_params.append("reasoning_effort")
+            return litellm.supports_reasoning(model=model, custom_llm_provider=self.custom_llm_provider)
         except Exception as e:
             verbose_logger.debug("BedrockMantleChatConfig: error checking reasoning support: %s", e)
-        return base_params
+            return False
 
     def get_model_response_iterator(
         self,

tests/test_litellm/completion_extras/litellm_responses_transformation/test_completion_extras_litellm_responses_transformation_transformation.py

@@ -4287,3 +4287,36 @@ def test_system_string_after_a_developer_message_stays_in_input_in_client_order(
     assert instructions is None
     assert [item["role"] for item in input_items] == ["developer", "system", "user"]
     assert input_items[1] == _system_input_item("Be brief.")
+
+
+def test_map_optional_params_verbosity_merges_into_text():
+    """Chat verbosity must land on Responses text.verbosity alongside text.format regardless of key order."""
+    from litellm.completion_extras.litellm_responses_transformation.transformation import (
+        LiteLLMResponsesTransformationHandler,
+    )
+    from litellm.types.llms.openai import ResponsesAPIOptionalRequestParams
+
+    handler: Final = LiteLLMResponsesTransformationHandler()
+
+    responses_api_request = ResponsesAPIOptionalRequestParams()
+    handler._map_optional_params_to_responses_api_request(
+        {"verbosity": "low", "response_format": {"type": "json_object"}},
+        responses_api_request,
+    )
+    assert responses_api_request["text"]["verbosity"] == "low"
+    assert responses_api_request["text"]["format"]["type"] == "json_object"
+
+    reversed_request = ResponsesAPIOptionalRequestParams()
+    handler._map_optional_params_to_responses_api_request(
+        {"response_format": {"type": "json_object"}, "verbosity": "low"},
+        reversed_request,
+    )
+    assert reversed_request["text"]["verbosity"] == "low"
+    assert reversed_request["text"]["format"]["type"] == "json_object"
+
+    verbosity_only_request = ResponsesAPIOptionalRequestParams()
+    handler._map_optional_params_to_responses_api_request(
+        {"verbosity": "low"},
+        verbosity_only_request,
+    )
+    assert verbosity_only_request["text"] == {"verbosity": "low"}

tests/test_litellm/llms/bedrock_mantle/test_bedrock_mantle_transformation.py

@@ -257,6 +257,18 @@ class TestBedrockMantleConfig:
         assert "temperature" in params
         assert "stream" in params
         assert "max_tokens" in params
+        assert "verbosity" not in params
+
+    def test_verbosity_passes_through_for_gpt_5_models(self):
+        cfg = BedrockMantleChatConfig()
+        assert "verbosity" in cfg.get_supported_openai_params("openai.gpt-5.6-sol")
+        optional_params = litellm.get_optional_params(
+            model="openai.gpt-5.6-sol",
+            custom_llm_provider="bedrock_mantle",
+            verbosity="low",
+            drop_params=False,
+        )
+        assert optional_params["verbosity"] == "low"
 
 
 class TestBedrockMantleChatAuth: