Update app.py

app.py

@@ -9,7 +9,6 @@ import os
 from pathlib import Path
 import time
 
-# NOTE: No changes were made to your prompts or rubric.
 GRADING_RUBRIC = """
 GRADING RUBRIC (Total 100 points)
 
@@ -168,6 +167,19 @@ class GeminiGrader:
                 feedback=data["feedback"],
                 summary=data["summary"]
             )
+        except json.JSONDecodeError as e:
+            print("\n" + "="*20 + " JSON PARSE ERROR " + "="*20)
+            print(f"[DEBUG] The model returned a malformed JSON. Error: {e}")
+            print("[DEBUG] --- FAULTY RESPONSE FROM MODEL ---")
+            print(cleaned_response)
+            print("[DEBUG] --- END OF FAULTY RESPONSE ---")
+            print("="*58 + "\n")
+            return GradingResult(
+                file_name=student_paper_file.display_name,
+                success=False,
+                error_message=f"Model returned malformed JSON. Details: {e}"
+            )
+            
         except Exception as e:
             print(f"[DEBUG] !!! An error occurred in grade_essay: {e}")
             return GradingResult(