fix(bedrock): strip unsupported Files API betas for Invoke

Bedrock Invoke rejects files-api and code-execution betas; omit them while
keeping other anthropic_beta flags. Add unit tests.

Made-with: Cursor

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

@@ -9,6 +9,7 @@ from litellm.llms.bedrock.chat.invoke_transformations.base_invoke_transformation
 from litellm.llms.bedrock.common_utils import (
     get_anthropic_beta_from_headers,
     remove_custom_field_from_tools,
+    strip_unsupported_file_api_betas_for_bedrock_invoke,
 )
 from litellm.types.llms.anthropic import ANTHROPIC_TOOL_SEARCH_BETA_HEADER
 from litellm.types.llms.openai import AllMessageValues
@@ -143,9 +144,11 @@ class AmazonAnthropicClaudeConfig(AmazonInvokeConfig, AnthropicConfig):
                 beta_set.add("tool-search-tool-2025-10-19")
 
         # Filter out beta headers that Bedrock Invoke doesn't support
-        # Uses centralized configuration from anthropic_beta_headers_config.json
-        beta_list = list(beta_set)
-        _anthropic_request["anthropic_beta"] = beta_list
+        beta_list = strip_unsupported_file_api_betas_for_bedrock_invoke(list(beta_set))
+        if beta_list:
+            _anthropic_request["anthropic_beta"] = beta_list
+        else:
+            _anthropic_request.pop("anthropic_beta", None)
 
         return _anthropic_request
 

litellm/llms/bedrock/common_utils.py

@@ -907,6 +907,21 @@ def get_anthropic_beta_from_headers(headers: dict) -> List[str]:
     return []
 
 
+# Anthropic's Files API uses these betas when using file_id / hosted files. Bedrock Invoke
+# rejects them with "invalid beta flag". Document blocks with source.url still work without them.
+BEDROCK_INVOKE_UNSUPPORTED_FILE_API_BETAS: frozenset[str] = frozenset(
+    {
+        "files-api-2025-04-14",
+        "code-execution-2025-05-22",
+    }
+)
+
+
+def strip_unsupported_file_api_betas_for_bedrock_invoke(betas: List[str]) -> List[str]:
+    """Drop Files-API-only betas from anthropic_beta before Bedrock Invoke."""
+    return [b for b in betas if b not in BEDROCK_INVOKE_UNSUPPORTED_FILE_API_BETAS]
+
+
 class CommonBatchFilesUtils:
     """
     Common utilities for Bedrock batch and file operations.

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

@@ -27,6 +27,7 @@ from litellm.llms.bedrock.common_utils import (
     get_anthropic_beta_from_headers,
     is_claude_4_5_on_bedrock,
     remove_custom_field_from_tools,
+    strip_unsupported_file_api_betas_for_bedrock_invoke,
 )
 from litellm.types.llms.anthropic import ANTHROPIC_TOOL_SEARCH_BETA_HEADER
 from litellm.types.llms.openai import AllMessageValues
@@ -460,8 +461,11 @@ class AmazonAnthropicClaudeMessagesConfig(
         if "tool-search-tool-2025-10-19" in beta_set:
             beta_set.add("tool-examples-2025-10-29")
 
-        if beta_set:
-            anthropic_messages_request["anthropic_beta"] = list(beta_set)
+        beta_list = strip_unsupported_file_api_betas_for_bedrock_invoke(list(beta_set))
+        if beta_list:
+            anthropic_messages_request["anthropic_beta"] = beta_list
+        else:
+            anthropic_messages_request.pop("anthropic_beta", None)
 
         return anthropic_messages_request
 

tests/test_litellm/llms/bedrock/test_anthropic_beta_support.py

@@ -14,7 +14,10 @@ from litellm.llms.bedrock.chat.converse_transformation import AmazonConverseConf
 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.common_utils import (
+    get_anthropic_beta_from_headers,
+    strip_unsupported_file_api_betas_for_bedrock_invoke,
+)
 from litellm.llms.bedrock.messages.invoke_transformations.anthropic_claude3_transformation import (
     AmazonAnthropicClaudeMessagesConfig,
 )
@@ -64,6 +67,39 @@ class TestAnthropicBetaHeaderSupport:
         # Beta flags are stored as sets, so order may vary
         assert set(result["anthropic_beta"]) == {"context-1m-2025-08-07", "computer-use-2024-10-22"}
 
+    def test_invoke_omits_file_api_betas_for_openai_style_file_url(self):
+        """Bedrock returns invalid beta flag if Files API betas are sent; URL docs work without them."""
+        config = AmazonAnthropicClaudeConfig()
+        messages = [
+            {
+                "role": "user",
+                "content": [
+                    {"type": "text", "text": "What's this file about?"},
+                    {
+                        "type": "file",
+                        "file": {
+                            "file_id": "https://upload.wikimedia.org/wikipedia/commons/2/20/Re_example.pdf"
+                        },
+                    },
+                ],
+            }
+        ]
+        result = config.transform_request(
+            model="anthropic.claude-3-5-sonnet-20241022-v2:0",
+            messages=messages,
+            optional_params={},
+            litellm_params={},
+            headers={},
+        )
+        betas = result.get("anthropic_beta", [])
+        assert "files-api-2025-04-14" not in betas
+        assert "code-execution-2025-05-22" not in betas
+
+    def test_strip_unsupported_file_api_betas_helper(self):
+        assert strip_unsupported_file_api_betas_for_bedrock_invoke(
+            ["context-1m-2025-08-07", "files-api-2025-04-14", "code-execution-2025-05-22"]
+        ) == ["context-1m-2025-08-07"]
+
     def test_converse_transformation_anthropic_beta(self):
         """Test that Converse API transformation includes anthropic_beta in additionalModelRequestFields."""
         config = AmazonConverseConfig()