fix serving issues when requesting real data

qwen3_6_scripts/protocol.py

@@ -373,6 +373,31 @@ class ChatCompletionRequest(OpenAIBaseModel):
 
         return None
 
+    @model_validator(mode="before")
+    @classmethod
+    def normalize_messages(cls, data):
+        """Normalize incoming messages before pydantic union validation.
+
+        Real-world clients (e.g. from other providers) send assistant tool_call
+        messages with content=null, which fails the strict Union type check.
+        Replace null content with "" so validation passes.
+        reasoning_content is intentionally kept — chat_utils.py wraps it as
+        <think>...</think> for multi-turn reasoning history.
+        """
+        messages = data.get("messages")
+        if not isinstance(messages, list):
+            return data
+        normalized = []
+        for msg in messages:
+            if not isinstance(msg, dict):
+                normalized.append(msg)
+                continue
+            if msg.get("content") is None:
+                msg = {**msg, "content": ""}
+            normalized.append(msg)
+        data = {**data, "messages": normalized}
+        return data
+
     @model_validator(mode="before")
     @classmethod
     def validate_stream_options(cls, data):