Update app.py

app.py

@@ -46,8 +46,9 @@ def find_non_commutative(table: dict) -> list:
     return sorted(bad)
 
 @tool
-def libretext_extract(url: str, selector: str) -> str:
-    """Extract text via CSS selector"""
+def libretext_extract(query: str) -> str:
+    """Input 'url||css_selector', returns the first matching element's text"""
+    url, selector = query.split("||", 1)
     r = requests.get(url, timeout=10)
     soup = BeautifulSoup(r.text, "html.parser")
     return soup.select_one(selector).get_text(strip=True)