Update app.py

app.py

@@ -307,7 +307,11 @@ def parse_arxiv_refs(ref_text: str):
     SUMMARY
     
     Returns list of dicts with paper details, limited to 20 papers.
+    Returns empty list if parsing fails.
     """
+    if not ref_text:
+        return []
+        
     # Split on the paper header pattern
     papers = re.split(r'\*\*.*?\|\s*.*?\|\s*.*?\*\*', ref_text)
     headers = re.findall(r'\*\*.*?\|\s*.*?\|\s*.*?\*\*', ref_text)
@@ -340,7 +344,6 @@ def parse_arxiv_refs(ref_text: str):
                 'date': date_str
             })
 
-
 def perform_ai_lookup(q, vocal_summary=True, extended_refs=False, 
                       titles_summary=True, full_audio=False):
     """Perform Arxiv search and generate audio summaries."""