fix: handle empty xAI streams without crashing

camel/models/xai_model.py

@@ -523,6 +523,7 @@ def _stream_to_chunks(
         """
         chunk_id = ""
         model = str(self.model_type)
+        response = None
         tool_calls_emitted = False
         for response, chunk in stream_iter:
             chunk_id = chunk_id or (response.id if response.id else "")
@@ -558,7 +559,7 @@ def _stream_to_chunks(
             )
 
         # After stream ends, store state from the accumulated response
-        if response:
+        if response is not None:
             encrypted = response.encrypted_content
             reasoning = response.reasoning_content
             if encrypted:
@@ -767,9 +768,7 @@ def _compute_delta_messages(
                 # messages are genuinely new.  ChatAgent's streaming
                 # path may also record duplicate assistant messages,
                 # so filtering by role is the safest approach.
-                delta = [
-                    m for m in delta if m.get("role") != "assistant"
-                ]
+                delta = [m for m in delta if m.get("role") != "assistant"]
                 if delta:
                     return delta
 

test/models/test_xai_model.py

@@ -0,0 +1,28 @@
+# ========= Copyright 2023-2026 @ CAMEL-AI.org. All Rights Reserved. =========
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ========= Copyright 2023-2026 @ CAMEL-AI.org. All Rights Reserved. =========
+
+from types import MethodType
+
+from camel.models.xai_model import XAIModel
+
+
+def test_stream_to_chunks_handles_empty_stream():
+    model = XAIModel.__new__(XAIModel)
+    model.model_type = "grok-3"
+    model._last_encrypted_content = None
+    model._last_reasoning_content = None
+    model._save_response_chain = lambda *_args, **_kwargs: None
+    model._make_chunk = MethodType(lambda self, **kwargs: kwargs, model)
+
+    assert list(XAIModel._stream_to_chunks(model, iter([]), 0)) == []