diff --git a/litellm/llms/bedrock/chat/converse_transformation.py b/litellm/llms/bedrock/chat/converse_transformation.py
index 1fe64c3610e..36463a765d8 100644
--- a/litellm/llms/bedrock/chat/converse_transformation.py
+++ b/litellm/llms/bedrock/chat/converse_transformation.py
@@ -74,6 +74,7 @@ from ..common_utils import (
     get_anthropic_beta_from_headers,
     get_bedrock_tool_name,
     is_claude_4_5_on_bedrock,
+    strip_bedrock_routing_prefix,
 )
 
 # Computer use tool prefixes supported by Bedrock
@@ -1202,8 +1203,16 @@ class AmazonConverseConfig(BaseConfig):
         output_config: Optional[OutputConfigBlock] = inference_params.pop(
             "outputConfig", None
         )
+        # Strip routing prefixes (e.g. ``converse/``) and pass the provider
+        # explicitly so the declarative ``supports_output_config`` flag in
+        # ``model_prices_and_context_window.json`` is actually consulted.
+        # Passing ``custom_llm_provider=None`` would make ``_supports_factory``
+        # silently return False for any model whose name doesn't resolve to a
+        # known provider prefix on its own.
         if not _supports_factory(
-            model=model, custom_llm_provider=None, key="supports_output_config"
+            model=strip_bedrock_routing_prefix(model),
+            custom_llm_provider="bedrock",
+            key="supports_output_config",
         ):
             inference_params.pop("output_config", None)
 
diff --git a/litellm/llms/bedrock/chat/invoke_transformations/anthropic_claude3_transformation.py b/litellm/llms/bedrock/chat/invoke_transformations/anthropic_claude3_transformation.py
index 9e8467fe394..6c7ff33b070 100644
--- a/litellm/llms/bedrock/chat/invoke_transformations/anthropic_claude3_transformation.py
+++ b/litellm/llms/bedrock/chat/invoke_transformations/anthropic_claude3_transformation.py
@@ -18,6 +18,7 @@ from litellm.llms.bedrock.common_utils import (
     get_anthropic_beta_from_headers,
     normalize_tool_input_schema_types_for_bedrock_invoke,
     remove_custom_field_from_tools,
+    strip_bedrock_routing_prefix,
 )
 from litellm.types.llms.anthropic import ANTHROPIC_TOOL_SEARCH_BETA_HEADER
 from litellm.types.llms.openai import AllMessageValues
@@ -170,8 +171,16 @@ class AmazonAnthropicClaudeConfig(AmazonInvokeConfig, AnthropicConfig):
         anthropic_request.pop("model", None)
         anthropic_request.pop("stream", None)
         anthropic_request.pop("output_format", None)
+        # ``model`` reaches this transformation with an ``invoke/`` routing
+        # prefix (e.g. ``invoke/us.anthropic.claude-opus-4-6-v1``) which is
+        # not a valid provider and makes ``_supports_factory`` silently
+        # return False. Strip the routing prefix and pass the provider
+        # explicitly so the declarative ``supports_output_config`` flag in
+        # ``model_prices_and_context_window.json`` is actually consulted.
         if not _supports_factory(
-            model=model, custom_llm_provider=None, key="supports_output_config"
+            model=strip_bedrock_routing_prefix(model),
+            custom_llm_provider="bedrock",
+            key="supports_output_config",
         ):
             anthropic_request.pop("output_config", None)
         if "anthropic_version" not in anthropic_request:
diff --git a/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py b/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
index f5b0659068c..e8f21b78451 100644
--- a/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
+++ b/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
@@ -32,6 +32,7 @@ from litellm.llms.bedrock.common_utils import (
     is_claude_4_5_on_bedrock,
     normalize_tool_input_schema_types_for_bedrock_invoke,
     remove_custom_field_from_tools,
+    strip_bedrock_routing_prefix,
 )
 from litellm.types.llms.anthropic import ANTHROPIC_TOOL_SEARCH_BETA_HEADER
 from litellm.types.llms.openai import AllMessageValues
@@ -504,8 +505,15 @@ class AmazonAnthropicClaudeMessagesConfig(
         # 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
+        # ``model`` still carries the ``invoke/`` routing prefix here, which
+        # is not a valid provider and makes ``_supports_factory`` silently
+        # return False. Strip the prefix and pass the provider explicitly so
+        # the declarative ``supports_output_config`` flag in the cost map
+        # is actually consulted.
         if not _supports_factory(
-            model=model, custom_llm_provider=None, key="supports_output_config"
+            model=strip_bedrock_routing_prefix(model),
+            custom_llm_provider="bedrock",
+            key="supports_output_config",
         ):
             anthropic_messages_request.pop("output_config", None)
 
diff --git a/tests/test_litellm/llms/bedrock/chat/invoke_transformations/test_bedrock_chat_invoke_transformations_anthropic_claude3_transformation.py b/tests/test_litellm/llms/bedrock/chat/invoke_transformations/test_bedrock_chat_invoke_transformations_anthropic_claude3_transformation.py
index 80d6d26e7ea..6174cfaee56 100644
--- a/tests/test_litellm/llms/bedrock/chat/invoke_transformations/test_bedrock_chat_invoke_transformations_anthropic_claude3_transformation.py
+++ b/tests/test_litellm/llms/bedrock/chat/invoke_transformations/test_bedrock_chat_invoke_transformations_anthropic_claude3_transformation.py
@@ -440,6 +440,48 @@ def test_output_config_removed_from_bedrock_chat_invoke_request():
     assert result["max_tokens"] == 100
 
 
+def test_output_config_preserved_for_claude_4_6_with_invoke_prefix():
+    """
+    Regression test: when the proxy routes ``bedrock/invoke/us.anthropic.
+    claude-opus-4-6-v1``, the transformation sees ``model=invoke/us.
+    anthropic.claude-opus-4-6-v1``. The ``invoke/`` prefix is not a valid
+    provider, so a naive ``_supports_factory(model, custom_llm_provider=None)``
+    call silently returns False and drops the user's ``output_config``.
+
+    This test forces the local cost map (so ``supports_output_config: true``
+    from the bundled JSON is visible) and asserts the Anthropic-style
+    ``output_config.effort`` is forwarded to Bedrock.
+    """
+    import os
+
+    import litellm
+
+    old_env = os.environ.get("LITELLM_LOCAL_MODEL_COST_MAP")
+    old_cost = litellm.model_cost
+    os.environ["LITELLM_LOCAL_MODEL_COST_MAP"] = "True"
+    litellm.model_cost = litellm.get_model_cost_map(url="")
+    try:
+        config = AmazonAnthropicClaudeConfig()
+        result = config.transform_request(
+            model="invoke/us.anthropic.claude-opus-4-6-v1",
+            messages=[{"role": "user", "content": "hello"}],
+            optional_params={
+                "max_tokens": 64,
+                "output_config": {"effort": "medium"},
+            },
+            litellm_params={},
+            headers={},
+        )
+
+        assert result.get("output_config") == {"effort": "medium"}
+    finally:
+        litellm.model_cost = old_cost
+        if old_env is None:
+            os.environ.pop("LITELLM_LOCAL_MODEL_COST_MAP", None)
+        else:
+            os.environ["LITELLM_LOCAL_MODEL_COST_MAP"] = old_env
+
+
 def test_output_format_removed_from_bedrock_invoke_request():
     """
     Test that output_format parameter is removed from Bedrock Invoke requests.