From 0d29da0af53bab2fca6775378a370f0c096bcdb8 Mon Sep 17 00:00:00 2001
From: Smeet Agrawal <smeetagrawal23@gmail.com>
Date: Thu, 9 Apr 2026 10:28:27 +0530
Subject: [PATCH] fix: add claude-haiku-4-5 to native structured output
 allowlist

claude-haiku-4-5-20251001 supports native structured output via the
output_format parameter but was missing from the model substring allowlist
in map_openai_params, causing it to fall back to the json_tool_call
synthesis workaround. This broke downstream tool dispatch when the model
also returned legitimate tool calls.

Adds test in tests/test_litellm/llms/anthropic/test_anthropic_structured_output.py.

Fixes https://github.com/BerriAI/litellm/issues/25308

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .../test_anthropic_completion.py              | 38 ------------------
 .../test_anthropic_structured_output.py       | 39 +++++++++++++++++++
 2 files changed, 39 insertions(+), 38 deletions(-)

diff --git a/tests/llm_translation/test_anthropic_completion.py b/tests/llm_translation/test_anthropic_completion.py
index 1765a3cb3a5..fdf8c24ac9e 100644
--- a/tests/llm_translation/test_anthropic_completion.py
+++ b/tests/llm_translation/test_anthropic_completion.py
@@ -447,44 +447,6 @@ def test_anthropic_tool_helper(cache_control_location):
     assert tool["cache_control"] == {"type": "ephemeral"}
 
 
-def test_haiku_4_5_uses_native_structured_output():
-    """
-    Haiku 4.5 supports native structured output via output_format.
-    It should NOT fall back to json_tool_call synthesis.
-    Regression test for https://github.com/BerriAI/litellm/issues/25308
-    """
-    from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-
-    config = AnthropicConfig()
-    response_format = {
-        "type": "json_schema",
-        "json_schema": {
-            "name": "MovieReview",
-            "schema": {
-                "type": "object",
-                "properties": {
-                    "title": {"type": "string"},
-                    "rating": {"type": "number"},
-                },
-                "required": ["title", "rating"],
-            },
-        },
-    }
-    optional_params = config.map_openai_params(
-        non_default_params={"response_format": response_format},
-        optional_params={},
-        model="claude-haiku-4-5-20251001",
-        drop_params=False,
-    )
-    # Should use native output_format, not json_tool_call
-    assert "output_format" in optional_params, (
-        "haiku-4-5 should use native output_format, not json_tool_call"
-    )
-    assert "tools" not in optional_params or not any(
-        t.get("name") == "json_tool_call" for t in optional_params.get("tools", [])
-    ), "haiku-4-5 should not synthesize a json_tool_call"
-
-
 def test_create_json_tool_call_for_response_format():
     """
     tests using response_format=json with anthropic
diff --git a/tests/test_litellm/llms/anthropic/test_anthropic_structured_output.py b/tests/test_litellm/llms/anthropic/test_anthropic_structured_output.py
index 705edeaf69c..ed0c7849f7b 100644
--- a/tests/test_litellm/llms/anthropic/test_anthropic_structured_output.py
+++ b/tests/test_litellm/llms/anthropic/test_anthropic_structured_output.py
@@ -128,6 +128,45 @@ class TestAnthropicStructuredOutput:
             if "properties" in nested_item_schema and "tags" in nested_item_schema["properties"]:
                 assert "maxItems" not in nested_item_schema["properties"]["tags"]
 
+    def test_haiku_4_5_uses_native_structured_output(self):
+        """
+        claude-haiku-4-5 supports native structured output via output_format.
+        It should NOT fall back to the json_tool_call synthesis workaround.
+
+        Regression test for https://github.com/BerriAI/litellm/issues/25308
+        """
+        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
+
+        config = AnthropicConfig()
+        response_format = {
+            "type": "json_schema",
+            "json_schema": {
+                "name": "MovieReview",
+                "schema": {
+                    "type": "object",
+                    "properties": {
+                        "title": {"type": "string"},
+                        "rating": {"type": "number"},
+                    },
+                    "required": ["title", "rating"],
+                },
+            },
+        }
+        optional_params = config.map_openai_params(
+            non_default_params={"response_format": response_format},
+            optional_params={},
+            model="claude-haiku-4-5-20251001",
+            drop_params=False,
+        )
+        # Should use native output_format, not json_tool_call
+        assert "output_format" in optional_params, (
+            "claude-haiku-4-5 should use native output_format, not json_tool_call"
+        )
+        assert not any(
+            t.get("name") == "json_tool_call"
+            for t in optional_params.get("tools", [])
+        ), "claude-haiku-4-5 should not synthesize a json_tool_call"
+
     def test_other_constraints_preserved(self):
         """
         Test that constraints are properly handled (removed from schema, added to description).