fix: tool with antropic #19800 (#19805)

litellm/llms/anthropic/chat/transformation.py

@@ -290,10 +290,19 @@ class AnthropicConfig(AnthropicModelInfo, BaseConfig):
         elif tool_choice == "none":
             _tool_choice = AnthropicMessagesToolChoice(type="none")
         elif isinstance(tool_choice, dict):
-            _tool_name = tool_choice.get("function", {}).get("name")
-            _tool_choice = AnthropicMessagesToolChoice(type="tool")
-            if _tool_name is not None:
-                _tool_choice["name"] = _tool_name
+            if "type" in tool_choice and "function" not in tool_choice:
+                tool_type = tool_choice.get("type")
+                if tool_type == "auto":
+                    _tool_choice = AnthropicMessagesToolChoice(type="auto")
+                elif tool_type == "required" or tool_type == "any":
+                    _tool_choice = AnthropicMessagesToolChoice(type="any")
+                elif tool_type == "none":
+                    _tool_choice = AnthropicMessagesToolChoice(type="none")
+            else:
+                _tool_name = tool_choice.get("function", {}).get("name")
+                if _tool_name is not None:
+                    _tool_choice = AnthropicMessagesToolChoice(type="tool")
+                    _tool_choice["name"] = _tool_name
 
         if parallel_tool_use is not None:
             # Anthropic uses 'disable_parallel_tool_use' flag to determine if parallel tool use is allowed

tests/test_litellm/llms/anthropic/chat/test_anthropic_chat_transformation.py

@@ -548,6 +548,59 @@ def test_map_tool_choice_dict_type_function_with_name():
     assert result["name"] == "my_tool"
 
 
+def test_map_tool_choice_dict_type_auto():
+    """
+    Test that dict {"type": "auto"} maps to Anthropic type='auto'.
+    This handles Cursor's format for tool_choice.
+    """
+    config = AnthropicConfig()
+    result = config._map_tool_choice(
+        tool_choice={"type": "auto"},
+        parallel_tool_use=None,
+    )
+    assert result is not None
+    assert result["type"] == "auto"
+
+
+def test_map_tool_choice_dict_type_required():
+    """
+    Test that dict {"type": "required"} maps to Anthropic type='any'.
+    """
+    config = AnthropicConfig()
+    result = config._map_tool_choice(
+        tool_choice={"type": "required"},
+        parallel_tool_use=None,
+    )
+    assert result is not None
+    assert result["type"] == "any"
+
+
+def test_map_tool_choice_dict_type_none():
+    """
+    Test that dict {"type": "none"} maps to Anthropic type='none'.
+    """
+    config = AnthropicConfig()
+    result = config._map_tool_choice(
+        tool_choice={"type": "none"},
+        parallel_tool_use=None,
+    )
+    assert result is not None
+    assert result["type"] == "none"
+
+
+def test_map_tool_choice_dict_type_function_without_name():
+    """
+    Test that dict {"type": "function"} without name is handled gracefully.
+    Should return None since there's no valid tool name.
+    """
+    config = AnthropicConfig()
+    result = config._map_tool_choice(
+        tool_choice={"type": "function"},
+        parallel_tool_use=None,
+    )
+    assert result is None
+
+
 def test_transform_response_with_prefix_prompt():
     import httpx