diff --git a/litellm/llms/anthropic/messages/adapters/handler.py b/litellm/llms/anthropic/messages/adapters/handler.py
index 31a4e9d9d73..c654438f841 100644
--- a/litellm/llms/anthropic/messages/adapters/handler.py
+++ b/litellm/llms/anthropic/messages/adapters/handler.py
@@ -21,6 +21,7 @@ from litellm.litellm_core_utils.tool_fields import (
     tools_without_mcp_servers,
 )
 from litellm.llms.anthropic.messages.adapters.transformation import (
+    ANTHROPIC_ONLY_REQUEST_KEYS,
     AnthropicAdapter,
 )
 from litellm.llms.anthropic.messages.context_management import (
@@ -56,8 +57,6 @@ if TYPE_CHECKING:
     from litellm.router import Router
     from litellm.types.proxy.auth.user_api_key_auth import UserAPIKeyAuth
 
-# Anthropic-only keys already mapped by the translator; strip on extra_kwargs re-merge.
-ANTHROPIC_ONLY_REQUEST_KEYS: Final[frozenset[str]] = frozenset({"output_config", "safeguards"})
 _REQUEST_KWARGS: Final = TypeAdapter(Mapping[str, object])
 
 _AnthropicMessages: TypeAlias = "list[dict[str, object]]"
diff --git a/litellm/llms/anthropic/messages/adapters/transformation.py b/litellm/llms/anthropic/messages/adapters/transformation.py
index afcd94c5b2c..824cb19587f 100644
--- a/litellm/llms/anthropic/messages/adapters/transformation.py
+++ b/litellm/llms/anthropic/messages/adapters/transformation.py
@@ -215,6 +215,10 @@ from litellm.utils import supports_mid_conversation_system
 
 from .streaming_iterator import AnthropicSSEStream, AnthropicStreamWrapper
 
+ANTHROPIC_ONLY_REQUEST_KEYS: Final[frozenset[str]] = frozenset(
+    {"output_config", "safeguards", "inference_geo", "mcp_servers", "speed"}
+)
+
 if TYPE_CHECKING:
     from litellm.litellm_core_utils.litellm_logging import Logging as LiteLLMLoggingObject
     from litellm.llms.anthropic.messages.safeguards import SafeguardsEvaluator
@@ -1272,7 +1276,7 @@ class LiteLLMAnthropicMessagesAdapter:
         """Copy through anthropic params that do not require translation."""
         translatable_params: Final = self.translatable_anthropic_params()
         for k, v in anthropic_message_request.items():
-            if k not in translatable_params:  # pass remaining params as is
+            if k not in translatable_params and k not in ANTHROPIC_ONLY_REQUEST_KEYS:
                 new_kwargs[k] = v
 
     def translate_anthropic_to_openai(
diff --git a/tests/integration/translation/messages/params/__init__.py b/tests/integration/translation/messages/params/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/integration/translation/messages/params/test_messages_params_anthropic_only.py b/tests/integration/translation/messages/params/test_messages_params_anthropic_only.py
new file mode 100644
index 00000000000..5d384b3cfee
--- /dev/null
+++ b/tests/integration/translation/messages/params/test_messages_params_anthropic_only.py
@@ -0,0 +1,27 @@
+from dataclasses import replace
+from typing import Final
+
+import pytest
+from integration._support.client import Gateway
+from integration._support.provider import SharedProvider
+from integration.translation.case import TranslationTestCase
+from integration.translation.messages.bases.azure import GPT_5_4_TEST_CASE
+from integration.translation.runner import assert_translation
+
+GPT_5_4_ANTHROPIC_ONLY_PARAMS_TEST_CASE: Final = replace(
+    GPT_5_4_TEST_CASE,
+    scenario="anthropic_only_params_dropped",
+    litellm_request={
+        **GPT_5_4_TEST_CASE.litellm_request,
+        "inference_geo": "us",
+        "mcp_servers": [{"type": "url", "url": "https://mcp.example.com/sse", "name": "example"}],
+        "speed": "fast",
+    },
+)
+
+CASES: Final = (GPT_5_4_ANTHROPIC_ONLY_PARAMS_TEST_CASE,)
+
+
+@pytest.mark.parametrize("case", CASES, ids=lambda case: case.id)
+def test_messages_params_anthropic_only(case: TranslationTestCase, gateway: Gateway, provider: SharedProvider) -> None:
+    assert_translation(case, gateway, provider)
diff --git a/tests/unit/llms/anthropic/messages/adapters/test_anthropic_messages_adapters_transformation.py b/tests/unit/llms/anthropic/messages/adapters/test_anthropic_messages_adapters_transformation.py
index cc366dcde4c..523f3e35f0b 100644
--- a/tests/unit/llms/anthropic/messages/adapters/test_anthropic_messages_adapters_transformation.py
+++ b/tests/unit/llms/anthropic/messages/adapters/test_anthropic_messages_adapters_transformation.py
@@ -4108,6 +4108,27 @@ def test_translate_anthropic_tool_choice_none():
     assert result == "none"
 
 
+def test_translate_anthropic_to_openai_drops_anthropic_only_params() -> None:
+    adapter: Final = LiteLLMAnthropicMessagesAdapter()
+
+    new_kwargs, _ = adapter.translate_anthropic_to_openai(
+        {
+            "model": "gpt-5.4",
+            "max_tokens": 64,
+            "messages": [{"role": "user", "content": "Say hello."}],
+            "inference_geo": "us",
+            "mcp_servers": [{"type": "url", "url": "https://mcp.example.com/sse", "name": "example"}],
+            "speed": "fast",
+            "top_k": 7,
+        }
+    )
+
+    assert "inference_geo" not in new_kwargs
+    assert "mcp_servers" not in new_kwargs
+    assert "speed" not in new_kwargs
+    assert new_kwargs["top_k"] == 7
+
+
 # ---------------------------------------------------------------------------
 # PolyfillResult integration tests
 # ---------------------------------------------------------------------------