From 26f1a3bc7d21c1da93a23cd10514f3c1c9c22503 Mon Sep 17 00:00:00 2001
From: le-shi <13051960278@163.com>
Date: Thu, 6 Aug 2026 21:42:11 +0800
Subject: [PATCH] fix(anthropic): use native structured output for Sonnet 5

---
 ...odel_prices_and_context_window_backup.json |  1 +
 model_prices_and_context_window.json          |  1 +
 .../test_anthropic_chat_transformation.py     | 25 +++++++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/litellm/model_prices_and_context_window_backup.json b/litellm/model_prices_and_context_window_backup.json
index d954e33da9c..8858bdc9166 100644
--- a/litellm/model_prices_and_context_window_backup.json
+++ b/litellm/model_prices_and_context_window_backup.json
@@ -11680,6 +11680,7 @@
         "supports_prompt_caching": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
+        "supports_native_structured_output": true,
         "supports_sampling_params": false,
         "supports_tool_choice": true,
         "supports_vision": true,
diff --git a/model_prices_and_context_window.json b/model_prices_and_context_window.json
index 8982b4f2565..443328c6f62 100644
--- a/model_prices_and_context_window.json
+++ b/model_prices_and_context_window.json
@@ -11680,6 +11680,7 @@
         "supports_prompt_caching": true,
         "supports_reasoning": true,
         "supports_response_schema": true,
+        "supports_native_structured_output": true,
         "supports_sampling_params": false,
         "supports_tool_choice": true,
         "supports_vision": true,
diff --git a/tests/test_litellm/llms/anthropic/chat/test_anthropic_chat_transformation.py b/tests/test_litellm/llms/anthropic/chat/test_anthropic_chat_transformation.py
index 231d3b48754..e5970ca4ac0 100644
--- a/tests/test_litellm/llms/anthropic/chat/test_anthropic_chat_transformation.py
+++ b/tests/test_litellm/llms/anthropic/chat/test_anthropic_chat_transformation.py
@@ -1042,6 +1042,31 @@ def test_native_structured_output_uses_bundled_capability_when_remote_map_lags(
     assert "tools" not in optional_params
 
 
+def test_claude_sonnet_5_uses_native_structured_output() -> None:
+    optional_params = AnthropicConfig().map_openai_params(
+        non_default_params={
+            "response_format": {
+                "type": "json_schema",
+                "json_schema": {
+                    "name": "answer",
+                    "schema": {
+                        "type": "object",
+                        "properties": {"answer": {"type": "string"}},
+                        "required": ["answer"],
+                    },
+                },
+            }
+        },
+        optional_params={},
+        model="claude-sonnet-5",
+        drop_params=False,
+    )
+
+    assert "output_format" in optional_params
+    assert "tools" not in optional_params
+    assert "tool_choice" not in optional_params
+
+
 def test_non_structured_output_model_uses_tool_workaround():
     """
     Test that models NOT in the native structured output list still use the