Fix VertexAI Anthropic Beta Headers

litellm/llms/anthropic/common_utils.py

@@ -536,3 +536,25 @@ def process_anthropic_headers(headers: Union[httpx.Headers, dict]) -> dict:
 
     additional_headers = {**llm_response_headers, **openai_headers}
     return additional_headers
+
+
+def get_anthropic_beta_from_headers(headers: dict) -> List[str]:
+    """
+    Extract anthropic-beta header values and convert them to a list.
+    Supports comma-separated values from user headers.
+
+    Used by both converse and invoke transformations for consistent handling
+    of anthropic-beta headers that should be passed to AWS Bedrock.
+
+    Args:
+        headers (dict): Request headers dictionary
+
+    Returns:
+        List[str]: List of anthropic beta feature strings, empty list if no header
+    """
+    anthropic_beta_header = headers.get("anthropic-beta")
+    if not anthropic_beta_header:
+        return []
+
+    # Split comma-separated values and strip whitespace
+    return [beta.strip() for beta in anthropic_beta_header.split(",")]

litellm/llms/bedrock/chat/converse_transformation.py

@@ -55,10 +55,11 @@
 )
 from litellm.utils import add_dummy_tool, has_tool_call_blocks, supports_reasoning
 
+from litellm.llms.anthropic.common_utils import get_anthropic_beta_from_headers
+
 from ..common_utils import (
     BedrockError,
     BedrockModelInfo,
-    get_anthropic_beta_from_headers,
     get_bedrock_tool_name,
 )
 

litellm/llms/bedrock/chat/invoke_transformations/anthropic_claude3_transformation.py

@@ -3,10 +3,10 @@
 import httpx
 
 from litellm.llms.anthropic.chat.transformation import AnthropicConfig
+from litellm.llms.anthropic.common_utils import get_anthropic_beta_from_headers
 from litellm.llms.bedrock.chat.invoke_transformations.base_invoke_transformation import (
     AmazonInvokeConfig,
 )
-from litellm.llms.bedrock.common_utils import get_anthropic_beta_from_headers
 from litellm.types.llms.anthropic import ANTHROPIC_TOOL_SEARCH_BETA_HEADER
 from litellm.types.llms.openai import AllMessageValues
 from litellm.types.utils import ModelResponse

litellm/llms/bedrock/common_utils.py

@@ -708,28 +708,6 @@ def _parse_message_from_event(self, event) -> Optional[str]:
             return chunk.decode()  # type: ignore[no-any-return]
 
 
-def get_anthropic_beta_from_headers(headers: dict) -> List[str]:
-    """
-    Extract anthropic-beta header values and convert them to a list.
-    Supports comma-separated values from user headers.
-
-    Used by both converse and invoke transformations for consistent handling
-    of anthropic-beta headers that should be passed to AWS Bedrock.
-
-    Args:
-        headers (dict): Request headers dictionary
-
-    Returns:
-        List[str]: List of anthropic beta feature strings, empty list if no header
-    """
-    anthropic_beta_header = headers.get("anthropic-beta")
-    if not anthropic_beta_header:
-        return []
-
-    # Split comma-separated values and strip whitespace
-    return [beta.strip() for beta in anthropic_beta_header.split(",")]
-
-
 class CommonBatchFilesUtils:
     """
     Common utilities for Bedrock batch and file operations.

litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py

@@ -12,7 +12,10 @@
 
 import httpx
 
-from litellm.llms.anthropic.common_utils import AnthropicModelInfo
+from litellm.llms.anthropic.common_utils import (
+    AnthropicModelInfo,
+    get_anthropic_beta_from_headers,
+)
 from litellm.llms.anthropic.experimental_pass_through.messages.transformation import (
     AnthropicMessagesConfig,
 )
@@ -23,7 +26,6 @@
 from litellm.llms.bedrock.chat.invoke_transformations.base_invoke_transformation import (
     AmazonInvokeConfig,
 )
-from litellm.llms.bedrock.common_utils import get_anthropic_beta_from_headers
 from litellm.types.llms.anthropic import ANTHROPIC_TOOL_SEARCH_BETA_HEADER
 from litellm.types.llms.openai import AllMessageValues
 from litellm.types.router import GenericLiteLLMParams

litellm/llms/vertex_ai/vertex_ai_partner_models/anthropic/transformation.py

@@ -5,6 +5,7 @@
 import httpx
 
 import litellm
+from litellm.llms.anthropic.common_utils import get_anthropic_beta_from_headers
 from litellm.llms.base_llm.chat.transformation import LiteLLMLoggingObj
 from litellm.types.llms.openai import AllMessageValues
 from litellm.types.utils import ModelResponse
@@ -71,16 +72,21 @@ def transform_request(
 
         tools = optional_params.get("tools")
         tool_search_used = self.is_tool_search_used(tools)
+
+        # Start with user's anthropic-beta header
+        beta_set = set(get_anthropic_beta_from_headers(headers))
+
+        # Add auto-detected betas, with prompt_caching disabled for Vertex
         auto_betas = self.get_anthropic_beta_list(
             model=model,
             optional_params=optional_params,
             computer_tool_used=self.is_computer_tool_used(tools),
-            prompt_caching_set=self.is_cache_control_set(messages),
+            prompt_caching_set=False,  # Disable prompt caching for Vertex
             file_id_used=self.is_file_id_used(messages),
             mcp_server_used=self.is_mcp_server_used(optional_params.get("mcp_servers")),
         )
-
-        beta_set = set(auto_betas)
+        beta_set.update(auto_betas)
+
         if tool_search_used:
             beta_set.add("tool-search-tool-2025-10-19")  # Vertex requires this header for tool search
 

tests/test_litellm/llms/bedrock/test_anthropic_beta_support.py

@@ -10,11 +10,11 @@
 
 import pytest
 
+from litellm.llms.anthropic.common_utils import get_anthropic_beta_from_headers
 from litellm.llms.bedrock.chat.converse_transformation import AmazonConverseConfig
 from litellm.llms.bedrock.chat.invoke_transformations.anthropic_claude3_transformation import (
     AmazonAnthropicClaudeConfig,
 )
-from litellm.llms.bedrock.common_utils import get_anthropic_beta_from_headers
 from litellm.llms.bedrock.messages.invoke_transformations.anthropic_claude3_transformation import (
     AmazonAnthropicClaudeMessagesConfig,
 )

tests/test_litellm/llms/vertex_ai/vertex_ai_partner_models/anthropic/test_vertex_ai_partner_models_anthropic_transformation.py

@@ -9,6 +9,7 @@
 from litellm.llms.vertex_ai.vertex_ai_partner_models.anthropic.transformation import (
     VertexAIAnthropicConfig,
 )
+from litellm.types.llms.openai import AllMessageValues
 
 
 @pytest.mark.parametrize(
@@ -115,3 +116,114 @@ def test_vertex_ai_anthropic_structured_output_header_not_added():
         "Non-Vertex request SHOULD have anthropic-beta header for structured output"
     assert result_non_vertex["anthropic-beta"] == "structured-outputs-2025-11-13", \
         f"Expected 'structured-outputs-2025-11-13', got: {result_non_vertex.get('anthropic-beta')}"
+
+
+def test_vertex_ai_anthropic_user_beta_headers_preserved():
+    """Test that user-provided anthropic-beta headers are preserved and combined with auto-detected ones"""
+    config = VertexAIAnthropicConfig()
+
+    # Test with user-provided beta header
+    headers = {
+        "anthropic-beta": "custom-feature-1,custom-feature-2"
+    }
+
+    messages = [
+        {"role": "user", "content": "Hello"}
+    ]
+
+    optional_params = {
+        "tools": [{"type": "computer_20250124", "name": "computer"}]
+    }
+
+    litellm_params = {}
+
+    result = config.transform_request(
+        model="claude-3-5-sonnet",
+        messages=messages,
+        optional_params=optional_params,
+        litellm_params=litellm_params,
+        headers=headers,
+    )
+
+    # Check that anthropic_beta is in the result
+    assert "anthropic_beta" in result, "anthropic_beta should be in the result"
+
+    # Check that user headers are preserved
+    assert "custom-feature-1" in result["anthropic_beta"], \
+        f"User header 'custom-feature-1' should be preserved, got: {result['anthropic_beta']}"
+    assert "custom-feature-2" in result["anthropic_beta"], \
+        f"User header 'custom-feature-2' should be preserved, got: {result['anthropic_beta']}"
+
+    # Check that auto-detected beta (computer-use) is also added
+    assert "computer-use-2025-01-24" in result["anthropic_beta"], \
+        f"Auto-detected 'computer-use-2025-01-24' should be added, got: {result['anthropic_beta']}"
+
+
+def test_vertex_ai_anthropic_prompt_caching_disabled():
+    """Test that prompt caching beta header is NOT added for Vertex AI even when cache_control is set"""
+    config = VertexAIAnthropicConfig()
+
+    # Messages with cache_control set
+    messages: list[AllMessageValues] = [
+        {
+            "role": "user",
+            "content": [
+                {
+                    "type": "text",
+                    "text": "Hello",
+                    "cache_control": {"type": "ephemeral"}
+                }
+            ]
+        }
+    ]
+
+    optional_params = {}
+    litellm_params = {}
+    headers = {}
+
+    result = config.transform_request(
+        model="claude-3-5-sonnet",
+        messages=messages,
+        optional_params=optional_params,
+        litellm_params=litellm_params,
+        headers=headers,
+    )
+
+    # Check that prompt caching beta header is NOT added
+    if "anthropic_beta" in result:
+        assert "prompt-caching-2024-07-31" not in result["anthropic_beta"], \
+            f"Prompt caching beta header should NOT be added for Vertex AI, got: {result['anthropic_beta']}"
+
+
+def test_vertex_ai_anthropic_tool_search_beta_header():
+    """Test that tool search adds the correct beta header for Vertex AI"""
+    config = VertexAIAnthropicConfig()
+
+    messages = [
+        {"role": "user", "content": "Search for something"}
+    ]
+
+    optional_params = {
+        "tools": [
+            {
+                "type": "tool_search_tool_regex_20251119",
+                "name": "tool_search",
+            }
+        ]
+    }
+
+    litellm_params = {}
+    headers = {}
+
+    result = config.transform_request(
+        model="claude-3-5-sonnet",
+        messages=messages,
+        optional_params=optional_params,
+        litellm_params=litellm_params,
+        headers=headers,
+    )
+
+    # Check that tool search beta header is added
+    assert "anthropic_beta" in result, "anthropic_beta should be in the result"
+    assert "tool-search-tool-2025-10-19" in result["anthropic_beta"], \
+        f"Tool search beta header should be added for Vertex AI, got: {result['anthropic_beta']}"