From 814e36353b9983773a693ef514a2f04d411532f0 Mon Sep 17 00:00:00 2001
From: Sameer Kankute <sameer@berri.ai>
Date: Sat, 7 Mar 2026 00:36:22 +0530
Subject: [PATCH] Fix output config error

---
 .../experimental_pass_through/adapters/handler.py  |  5 ++++-
 .../adapters/transformation.py                     | 14 +++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py b/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py
index 73e74c228ba..cf047127bac 100644
--- a/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py
+++ b/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py
@@ -163,7 +163,10 @@ class LiteLLMMessagesToCompletionTransformationHandler:
                 "include_usage": True,
             }
 
-        excluded_keys = {"anthropic_messages"}
+        excluded_keys = {
+            "anthropic_messages",
+            "output_config",  # Anthropic-only; OpenAI does not support it
+        }
         extra_kwargs = extra_kwargs or {}
         for key, value in extra_kwargs.items():
             if (
diff --git a/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py b/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py
index 8b21569546e..3fd4af0e6cc 100644
--- a/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py
+++ b/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py
@@ -296,8 +296,20 @@ class LiteLLMAnthropicMessagesAdapter:
     def translatable_anthropic_params(self) -> List:
         """
         Which anthropic params, we need to translate to the openai format.
+        Params in this list are either translated or dropped when targeting OpenAI.
+        Anthropic-only params like output_config are included here to be dropped
+        (OpenAI does not support them).
         """
-        return ["messages", "metadata", "system", "tool_choice", "tools", "thinking", "output_format"]
+        return [
+            "messages",
+            "metadata",
+            "system",
+            "tool_choice",
+            "tools",
+            "thinking",
+            "output_format",
+            "output_config",  # Anthropic-only; drop when targeting OpenAI
+        ]
 
     def _is_web_search_tool(self, tool: Dict[str, Any]) -> bool:
         """