Fix: Use greedy regex for JSON extraction from markdown

student/code_generator.py

@@ -206,10 +206,17 @@ Generate ONLY the JSON output, no other text. Ensure all code is complete and fu
         Returns:
             Parsed JSON dictionary
         """
-        # Try to find JSON in markdown code block
+        # Try to find JSON in markdown code block (greedy match for nested braces)
         import re
 
-        json_match = re.search(r"```json\s*(\{.*?\})\s*```", content, re.DOTALL)
+        json_match = re.search(r"```json\s*(\{.*\})\s*```", content, re.DOTALL)
+        if json_match:
+            result = json.loads(json_match.group(1))
+            # Validate that all values are strings
+            return {k: v for k, v in result.items() if v is not None}
+
+        # Try to find JSON in plain code block
+        json_match = re.search(r"```\s*(\{.*\})\s*```", content, re.DOTALL)
         if json_match:
             result = json.loads(json_match.group(1))
             # Validate that all values are strings
@@ -221,7 +228,7 @@ Generate ONLY the JSON output, no other text. Ensure all code is complete and fu
             # Validate that all values are strings
             return {k: v for k, v in result.items() if v is not None}
         except json.JSONDecodeError:
-            # Try to find any JSON object
+            # Try to find any JSON object (greedy match)
             json_match = re.search(r"\{.*\}", content, re.DOTALL)
             if json_match:
                 result = json.loads(json_match.group(0))