Update app.py

app.py

@@ -25,7 +25,12 @@ def save_cache():
 def calculator(expression: str) -> str:
     """
     Safely evaluate a mathematical expression.
-    Input should be a simple arithmetic expression (e.g., '2 + 2').
+
+    Args:
+        expression: A string containing a simple arithmetic expression (e.g., '2 + 2').
+
+    Returns:
+        The result as a string, or an error message if the expression is invalid.
     """
     # Allow only numbers, basic operators, parentheses, and spaces
     allowed_chars = set("0123456789+-*/(). ")
@@ -42,7 +47,13 @@ def calculator(expression: str) -> str:
 def web_search(query: str) -> str:
     """
     Search the web for up-to-date information.
-    Uses DuckDuckGo (free, no API key). Requires duckduckgo-search package.
+
+    Args:
+        query: The search query string.
+
+    Returns:
+        A string containing up to three search result snippets with titles and URLs,
+        or an error message if the search fails.
     """
     try:
         from duckduckgo_search import DDGS
@@ -61,10 +72,7 @@ def web_search(query: str) -> str:
 
 # ---------- Agent ----------
 # Use ApiModel (the correct class name in current smolagents)
-# You can specify a model explicitly, e.g.:
-# model = ApiModel("meta-llama/Llama-2-7b-chat-hf")
-# The default uses Hugging Face's free inference API.
-model = ApiModel()
+model = ApiModel()  # Uses Hugging Face's free inference API
 
 # Only include web_search if the package is installed
 tools = [calculator]