fix(bedrock): serve region-path and GovCloud gpt-oss ids on native Chat Completions

The cost-map parity tests require every regional variant of a flagged id to carry the same supports_ flags, so the six us-gov gpt-oss entries now carry the native-route flags too. A region path in the model name (bedrock/us-gov-west-1/openai.gpt-oss-20b-1:0) is routing, not a different model: the route is looked up on the id after the path, the path's region picks the endpoint and the SigV4 scope, an explicit aws_region_name still wins, and the body carries the bare id AWS expects

litellm/llms/bedrock/chat/chat_completions/transformation.py

@@ -24,7 +24,7 @@ from typing_extensions import assert_never
 import litellm
 from litellm.llms.base_llm.chat.transformation import BaseLLMException
 from litellm.llms.bedrock.base_aws_llm import BaseAWSLLM
-from litellm.llms.bedrock.common_utils import BedrockError, strip_bedrock_routing_prefix
+from litellm.llms.bedrock.common_utils import BedrockError, split_bedrock_region_path
 from litellm.llms.openai.chat.gpt_transformation import OpenAIChatCompletionStreamingHandler
 from litellm.llms.openai_like.chat.transformation import OpenAILikeChatConfig
 from litellm.types.llms.openai import AllMessageValues
@@ -196,7 +196,7 @@ class AmazonBedrockRuntimeChatCompletionsConfig(OpenAILikeChatConfig):
         if api_base is not None and "chat/completions" in api_base:
             return api_base.rstrip("/")
         aws_region_name: Final = self._aws_signer._get_aws_region_name(  # pyright: ignore[reportPrivateUsage]  # BaseAWSLLM has no public region resolver
-            optional_params=optional_params, model=model
+            optional_params=self._params_with_region_from_path(optional_params, model), model=model
         )
         endpoint_url, _ = self._aws_signer.get_runtime_endpoint(
             api_base=api_base,
@@ -210,6 +210,14 @@ class AmazonBedrockRuntimeChatCompletionsConfig(OpenAILikeChatConfig):
             return f"{base}/chat/completions"
         return f"{base}/openai/v1/chat/completions"
 
+    def _params_with_region_from_path(
+        self, optional_params: dict, model: str | None
+    ) -> dict:  # mutable-ok: BaseAWSLLM's region resolver and signer take a plain dict
+        region_from_path, _ = split_bedrock_region_path(model or "")
+        if region_from_path is None or optional_params.get("aws_region_name") is not None:
+            return optional_params
+        return {**optional_params, "aws_region_name": region_from_path}  # mutable-ok: BaseAWSLLM takes a plain dict
+
     def sign_request(
         self,
         headers: dict,  # mutable-ok: BaseConfig signature
@@ -224,7 +232,7 @@ class AmazonBedrockRuntimeChatCompletionsConfig(OpenAILikeChatConfig):
         return self._aws_signer._sign_request(  # pyright: ignore[reportPrivateUsage]  # BaseAWSLLM has no public signer
             service_name="bedrock",
             headers=headers,
-            optional_params=optional_params,
+            optional_params=self._params_with_region_from_path(optional_params, model),
             request_data=request_data,
             api_base=api_base,
             api_key=api_key,
@@ -268,7 +276,7 @@ class AmazonBedrockRuntimeChatCompletionsConfig(OpenAILikeChatConfig):
         headers: dict,  # mutable-ok: BaseConfig signature
     ) -> dict:  # mutable-ok: BaseConfig signature
         return super().transform_request(
-            model=strip_bedrock_routing_prefix(model),
+            model=split_bedrock_region_path(model)[1],
             messages=messages,
             optional_params=self._inference_params(optional_params),
             litellm_params=litellm_params,
@@ -284,7 +292,7 @@ class AmazonBedrockRuntimeChatCompletionsConfig(OpenAILikeChatConfig):
         headers: dict,  # mutable-ok: BaseConfig signature
     ) -> dict:  # mutable-ok: BaseConfig signature
         return await super().async_transform_request(
-            model=strip_bedrock_routing_prefix(model),
+            model=split_bedrock_region_path(model)[1],
             messages=messages,
             optional_params=self._inference_params(optional_params),
             litellm_params=litellm_params,

litellm/llms/bedrock/common_utils.py

@@ -795,8 +795,24 @@ def strip_bedrock_routing_prefix(model: str) -> str:
     return model
 
 
+def split_bedrock_region_path(model: str) -> tuple[str | None, str]:
+    """Split a ``<region>/<model-id>`` routing path into the region and the id AWS receives.
+
+    ``bedrock/us-gov-west-1/openai.gpt-oss-20b-1:0`` -> ``("us-gov-west-1", "openai.gpt-oss-20b-1:0")``;
+    a model without a region path comes back as ``(None, <routing-prefix-stripped id>)``.
+    """
+    stripped: Final = strip_bedrock_routing_prefix(model)
+    region, separator, model_id = stripped.partition("/")
+    if separator and region in _get_all_bedrock_regions():
+        return region, model_id
+    return None, stripped
+
+
 def _bedrock_price_map_flag(model: str, flag: str) -> bool:
-    entries: Final = (litellm.model_cost.get(key) for key in (model, strip_bedrock_routing_prefix(model)))
+    entries: Final = (
+        litellm.model_cost.get(key)
+        for key in (model, strip_bedrock_routing_prefix(model), split_bedrock_region_path(model)[1])
+    )
     return any(entry is not None and entry.get(flag) is True for entry in entries)
 
 

litellm/model_prices_and_context_window_backup.json

@@ -47214,6 +47214,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 3.6e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -47227,6 +47229,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 7.2e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64459,6 +64463,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 3.6e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64472,6 +64478,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 7.2e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64665,6 +64673,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 3.6e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64678,6 +64688,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 7.2e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,

model_prices_and_context_window.json

@@ -47214,6 +47214,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 3.6e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -47227,6 +47229,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 7.2e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64459,6 +64463,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 3.6e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64472,6 +64478,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 7.2e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64665,6 +64673,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 3.6e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
@@ -64678,6 +64688,8 @@
         "max_tokens": 128000,
         "mode": "chat",
         "output_cost_per_token": 7.2e-07,
+        "supports_bedrock_runtime_chat_completions": true,
+        "supports_bedrock_runtime_chat_completions_tools_with_reasoning": true,
         "supports_function_calling": true,
         "supports_reasoning": true,
         "supports_response_schema": true,

tests/test_litellm/llms/bedrock/chat/chat_completions/test_bedrock_chat_completions_transformation.py

@@ -163,6 +163,33 @@ def test_completion_posts_runtime_chat_completions(local_cost_map, fake_aws_env)
     assert "inferenceConfig" not in body
 
 
+def test_region_path_sends_the_bare_model_id_to_the_path_region(local_cost_map, fake_aws_env):
+    requests, client = _recording_client(json=_chat_completion_json("ok", "openai.gpt-oss-20b-1:0"))
+    litellm.completion(
+        model="bedrock/us-gov-west-1/openai.gpt-oss-20b-1:0",
+        messages=[{"role": "user", "content": "hello"}],
+        client=client,
+    )
+
+    assert str(requests[0].url) == "https://bedrock-runtime.us-gov-west-1.amazonaws.com/openai/v1/chat/completions"
+    assert json.loads(requests[0].content)["model"] == "openai.gpt-oss-20b-1:0"
+    assert "/us-gov-west-1/bedrock/aws4_request" in requests[0].headers["Authorization"]
+
+
+def test_explicit_aws_region_name_wins_over_the_region_path(local_cost_map, fake_aws_env):
+    requests, client = _recording_client(json=_chat_completion_json("ok", "openai.gpt-oss-20b-1:0"))
+    litellm.completion(
+        model="bedrock/us-gov-west-1/openai.gpt-oss-20b-1:0",
+        messages=[{"role": "user", "content": "hello"}],
+        aws_region_name="us-gov-east-1",
+        client=client,
+    )
+
+    assert str(requests[0].url) == "https://bedrock-runtime.us-gov-east-1.amazonaws.com/openai/v1/chat/completions"
+    assert json.loads(requests[0].content)["model"] == "openai.gpt-oss-20b-1:0"
+    assert "/us-gov-east-1/bedrock/aws4_request" in requests[0].headers["Authorization"]
+
+
 OPENAI_RUNTIME_MODELS = (
     "openai.gpt-oss-20b-1:0",
     "openai.gpt-oss-120b-1:0",
@@ -182,7 +209,16 @@ GET_WEATHER_TOOL = {
 }
 
 
-@pytest.mark.parametrize("model", [*OPENAI_RUNTIME_MODELS, "bedrock/openai.gpt-oss-20b-1:0"])
+@pytest.mark.parametrize(
+    "model",
+    [
+        *OPENAI_RUNTIME_MODELS,
+        "bedrock/openai.gpt-oss-20b-1:0",
+        "us-gov.openai.gpt-oss-20b-1:0",
+        "bedrock/us-gov-west-1/openai.gpt-oss-20b-1:0",
+        "us-gov-east-1/openai.gpt-oss-120b-1:0",
+    ],
+)
 def test_openai_runtime_models_use_chat_completions_route(local_cost_map, model):
     assert uses_bedrock_runtime_chat_completions(model) is True
     assert BedrockModelInfo.get_bedrock_route(model) == "chat_completions"