fix(bedrock): preserve output_config.effort for Claude 4.6 on Invoke API

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

@@ -107,9 +107,11 @@ def transform_request(
         _anthropic_request.pop("stream", None)
         # Bedrock Invoke doesn't support output_format parameter
         _anthropic_request.pop("output_format", None)
-        # Bedrock Invoke doesn't support output_config parameter
-        # Fixes: https://github.com/BerriAI/litellm/issues/22797
-        _anthropic_request.pop("output_config", None)
+        # Bedrock Invoke supports output_config (effort) for Claude 4.6+ models,
+        # but older models do not — strip it to avoid request rejection.
+        # Ref: https://github.com/BerriAI/litellm/issues/22797
+        if not AnthropicConfig._is_claude_4_6_model(model):
+            _anthropic_request.pop("output_config", None)
         if "anthropic_version" not in _anthropic_request:
             _anthropic_request["anthropic_version"] = self.anthropic_version
 

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

@@ -419,9 +419,11 @@ def transform_anthropic_messages_request(
                 anthropic_messages_request=anthropic_messages_request,
             )
 
-        # 5b. Strip `output_config` — Bedrock Invoke doesn't support it
-        # Fixes: https://github.com/BerriAI/litellm/issues/22797
-        anthropic_messages_request.pop("output_config", None)
+        # 5b. Bedrock Invoke supports output_config (effort) for Claude 4.6+ models,
+        # but older models do not — strip it to avoid request rejection.
+        # Ref: https://github.com/BerriAI/litellm/issues/22797
+        if not AnthropicModelInfo._is_claude_4_6_model(model):
+            anthropic_messages_request.pop("output_config", None)
 
         # 5a. Remove `custom` field from tools (Bedrock doesn't support it)
         # Claude Code sends `custom: {defer_loading: true}` on tool definitions,

litellm/types/llms/anthropic.py

@@ -39,7 +39,7 @@ class AnthropicOutputSchema(TypedDict, total=False):
 class AnthropicOutputConfig(TypedDict, total=False):
     """Configuration for controlling Claude's output behavior."""
 
-    effort: Literal["high", "medium", "low"]
+    effort: Literal["high", "medium", "low", "max"]
 
 
 class AnthropicMessagesTool(TypedDict, total=False):

tests/test_litellm/llms/bedrock/chat/invoke_transformations/test_bedrock_chat_invoke_transformations_anthropic_claude3_transformation.py

@@ -420,6 +420,82 @@ def test_output_config_removed_from_bedrock_chat_invoke_request():
     assert result["max_tokens"] == 100
 
 
+def test_bedrock_chat_invoke_preserves_output_config_for_claude_4_6():
+    """
+    Claude 4.6 models support output_config.effort on Bedrock Invoke.
+    Verify that output_config is preserved (not stripped) for these models
+    on the /v1/chat/completions -> Bedrock Invoke path.
+    """
+    config = AmazonAnthropicClaudeConfig()
+    messages = [{"role": "user", "content": "test"}]
+
+    # Sonnet 4.6 supports effort=high (not max)
+    optional_params = {
+        "max_tokens": 128000,
+        "thinking": {"type": "adaptive"},
+        "output_config": {"effort": "high"},
+    }
+    result = config.transform_request(
+        model="global.anthropic.claude-sonnet-4-6",
+        messages=messages,
+        optional_params=optional_params,
+        litellm_params={},
+        headers={},
+    )
+    assert "output_config" in result, (
+        "output_config should be preserved for Claude Sonnet 4.6"
+    )
+    assert result["output_config"]["effort"] == "high"
+
+    # Opus 4.6 supports effort=max
+    optional_params = {
+        "max_tokens": 128000,
+        "thinking": {"type": "adaptive"},
+        "output_config": {"effort": "max"},
+    }
+    result = config.transform_request(
+        model="global.anthropic.claude-opus-4-6-v1",
+        messages=messages,
+        optional_params=optional_params,
+        litellm_params={},
+        headers={},
+    )
+    assert "output_config" in result, (
+        "output_config should be preserved for Claude Opus 4.6"
+    )
+    assert result["output_config"]["effort"] == "max"
+
+
+def test_bedrock_chat_invoke_strips_output_config_for_pre_4_6():
+    """
+    Pre-4.6 models do not support output_config on Bedrock Invoke.
+    Verify that output_config is still stripped for these models.
+    """
+    config = AmazonAnthropicClaudeConfig()
+    messages = [{"role": "user", "content": "test"}]
+
+    for model_id in [
+        "anthropic.claude-sonnet-4-20250514-v1:0",
+        "global.anthropic.claude-opus-4-5-20251101-v1:0",
+    ]:
+        optional_params = {
+            "max_tokens": 100,
+            "output_config": {"effort": "high"},
+        }
+
+        result = config.transform_request(
+            model=model_id,
+            messages=messages,
+            optional_params=optional_params,
+            litellm_params={},
+            headers={},
+        )
+
+        assert "output_config" not in result, (
+            f"output_config should be stripped for pre-4.6 model {model_id}"
+        )
+
+
 def test_output_format_removed_from_bedrock_invoke_request():
     """
     Test that output_format parameter is removed from Bedrock Invoke requests.

tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py

@@ -342,3 +342,90 @@ def test_bedrock_messages_strips_output_config_with_output_format():
 
     assert "output_config" not in result
     assert "output_format" not in result
+
+
+def test_bedrock_messages_preserves_output_config_for_claude_4_6():
+    """
+    Claude 4.6 models support output_config.effort on Bedrock Invoke.
+    Verify that output_config is preserved (not stripped) for these models.
+    """
+    from litellm.types.router import GenericLiteLLMParams
+
+    cfg = AmazonAnthropicClaudeMessagesConfig()
+    messages = [{"role": "user", "content": [{"type": "text", "text": "Hello"}]}]
+
+    # Opus 4.6 supports effort=max
+    for model_id in [
+        "global.anthropic.claude-opus-4-6-v1",
+        "anthropic.claude-opus-4-6-v1:0",
+    ]:
+        optional_params = {
+            "max_tokens": 128000,
+            "thinking": {"type": "adaptive"},
+            "output_config": {"effort": "max"},
+        }
+
+        result = cfg.transform_anthropic_messages_request(
+            model=model_id,
+            messages=messages,
+            anthropic_messages_optional_request_params=optional_params,
+            litellm_params=GenericLiteLLMParams(),
+            headers={},
+        )
+
+        assert "output_config" in result, (
+            f"output_config should be preserved for Claude 4.6 model {model_id}"
+        )
+        assert result["output_config"]["effort"] == "max"
+        assert result["thinking"]["type"] == "adaptive"
+
+    # Sonnet 4.6 supports effort=high (not max)
+    optional_params = {
+        "max_tokens": 128000,
+        "thinking": {"type": "adaptive"},
+        "output_config": {"effort": "high"},
+    }
+    result = cfg.transform_anthropic_messages_request(
+        model="global.anthropic.claude-sonnet-4-6",
+        messages=messages,
+        anthropic_messages_optional_request_params=optional_params,
+        litellm_params=GenericLiteLLMParams(),
+        headers={},
+    )
+    assert "output_config" in result, (
+        "output_config should be preserved for Claude Sonnet 4.6"
+    )
+    assert result["output_config"]["effort"] == "high"
+
+
+def test_bedrock_messages_strips_output_config_for_pre_4_6():
+    """
+    Pre-4.6 models do not support output_config on Bedrock Invoke.
+    Verify that output_config is stripped for these models.
+    """
+    from litellm.types.router import GenericLiteLLMParams
+
+    cfg = AmazonAnthropicClaudeMessagesConfig()
+    messages = [{"role": "user", "content": [{"type": "text", "text": "Hello"}]}]
+
+    for model_id in [
+        "anthropic.claude-3-haiku-20240307-v1:0",
+        "anthropic.claude-sonnet-4-20250514-v1:0",
+        "global.anthropic.claude-opus-4-5-20251101-v1:0",
+    ]:
+        optional_params = {
+            "max_tokens": 4096,
+            "output_config": {"effort": "high"},
+        }
+
+        result = cfg.transform_anthropic_messages_request(
+            model=model_id,
+            messages=messages,
+            anthropic_messages_optional_request_params=optional_params,
+            litellm_params=GenericLiteLLMParams(),
+            headers={},
+        )
+
+        assert "output_config" not in result, (
+            f"output_config should be stripped for pre-4.6 model {model_id}"
+        )