From 690656e2b3804ea25aaca3c9ad3828dd834a66bb Mon Sep 17 00:00:00 2001
From: eugene-yao-zocdoc <eugene.yao@zocdoc.com>
Date: Mon, 24 Aug 2026 19:26:22 -0400
Subject: [PATCH] fix(anthropic-responses): preserve nested strict setting

---
 .../responses_adapters/transformation.py                  | 2 +-
 .../test_responses_adapters_transformation.py             | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/litellm/llms/anthropic/experimental_pass_through/responses_adapters/transformation.py b/litellm/llms/anthropic/experimental_pass_through/responses_adapters/transformation.py
index 01917cd9a59..5ed8f26afca 100644
--- a/litellm/llms/anthropic/experimental_pass_through/responses_adapters/transformation.py
+++ b/litellm/llms/anthropic/experimental_pass_through/responses_adapters/transformation.py
@@ -520,7 +520,7 @@ class LiteLLMAnthropicToResponsesAPIAdapter:
                         "type": "json_schema",
                         "name": "structured_output",
                         "schema": schema,
-                        "strict": bool(output_format.get("strict")),
+                        "strict": output_format.get("strict", False),
                     }
                 }
 
diff --git a/tests/test_litellm/llms/anthropic/experimental_pass_through/responses_adapters/test_responses_adapters_transformation.py b/tests/test_litellm/llms/anthropic/experimental_pass_through/responses_adapters/test_responses_adapters_transformation.py
index a7efff6aa33..4057706f297 100644
--- a/tests/test_litellm/llms/anthropic/experimental_pass_through/responses_adapters/test_responses_adapters_transformation.py
+++ b/tests/test_litellm/llms/anthropic/experimental_pass_through/responses_adapters/test_responses_adapters_transformation.py
@@ -142,6 +142,14 @@ class TestOutputConfigStructuredOutput:
         assert fmt["strict"] is False
         assert fmt["name"] == "structured_output"
 
+    def test_output_config_format_explicit_strict_true_is_preserved(self):
+        """Nested output_config.format with explicit strict=True is preserved."""
+        req = _make_request(
+            output_config={"format": {"type": "json_schema", "schema": self._SCHEMA, "strict": True}}
+        )
+        kwargs = _ADAPTER.translate_request(req)
+        assert kwargs["text"]["format"]["strict"] is True
+
     def test_output_config_without_format_does_not_set_text(self):
         """output_config with only non-format keys doesn't produce text.format."""
         req = _make_request(output_config={"effort": "high"})