feat(xai): add parallel_tool_calls to supported params (#25106)

litellm/llms/xai/chat/transformation.py

@@ -43,6 +43,7 @@ class XAIChatConfig(OpenAIGPTConfig):
             "logprobs",
             "max_tokens",
             "n",
+            "parallel_tool_calls",
             "presence_penalty",
             "response_format",
             "seed",

tests/test_litellm/llms/xai/test_xai_chat_transformation.py

@@ -0,0 +1,39 @@
+import os
+import sys
+
+sys.path.insert(
+    0, os.path.abspath("../../../..")
+)  # Adds the parent directory to the system path
+
+from litellm.llms.xai.chat.transformation import XAIChatConfig
+
+
+class TestXAIParallelToolCalls:
+    """Test suite for XAI parallel tool calls functionality."""
+
+    def test_get_supported_openai_params_includes_parallel_tool_calls(self):
+        """Test that parallel_tool_calls is in supported parameters."""
+        config = XAIChatConfig()
+        supported_params = config.get_supported_openai_params(
+            "xai/grok-4.20"
+        )
+        assert "parallel_tool_calls" in supported_params
+
+    def test_transform_request_preserves_parallel_tool_calls(self):
+        """Test that transform_request preserves parallel_tool_calls parameter."""
+        config = XAIChatConfig()
+
+        messages = [{"role": "user", "content": "What's the weather like?"}]
+        optional_params = {"parallel_tool_calls": True}
+
+        result = config.transform_request(
+            model="xai/grok-4.20",
+            messages=messages,
+            optional_params=optional_params,
+            litellm_params={},
+            headers={},
+        )
+
+        assert result.get("parallel_tool_calls") is True
+        assert len(result["messages"]) == 1
+        assert result["messages"][0]["role"] == "user"