i have add this file to validate invalid or stupid prompts

cua2-core/src/cua2_core/services/agent_utils/prompt_validator.py

@@ -0,0 +1,24 @@
+from smolagents import Model
+
+def validate_prompt(prompt: str, model: Model) -> tuple[bool, str]:
+    """
+    Validate if a prompt is conceptually possible to solve on a computer.
+    Returns a tuple (is_valid: bool, reason: str).
+    """
+    messages = [
+        {
+            "role": "system",
+            "content": (
+                "You are a validation assistant for a computer-use AI. Determine if the user's task is "
+                "conceptually solvable using a computer (e.g., navigating web pages, using standard applications). "
+                "Tasks like 'order pizza on Amazon', 'download a physical car', or 'make me a coffee' are unsolvable. "
+                "If it is solvable, reply with 'VALID'. If it is unsolvable, reply with 'INVALID: <reason>'."
+            )
+        },
+        {"role": "user", "content": prompt}
+    ]
+    
+    response = model(messages).content
+    if response.startswith("INVALID:"):
+        return False, response[8:].strip()
+    return True, ""