update for better outputs

utils.py

@@ -29,10 +29,31 @@ def extract_pdf_text(pdf_path: str) -> str:
 
 def generate_manim_code(prompt_text: str, api_key: str) -> str:
     """Stream Manim code from Gemini 3 Flash Preview and return it as a string."""
+
     client = genai.Client(api_key=api_key)
     model = "gemini-3-flash-preview"
 
+    # Robust system prompt
+    system_prompt = """
+You are an expert Python developer and Manim animation engineer.
+Always produce code that:
+- Is fully correct and runnable with Manim v1.0+.
+- Uses clear, readable structure, proper imports, and PEP8-compliant formatting.
+- Produces visually correct animations based on the user's description.
+- Minimizes unnecessary complexity but keeps clarity.
+- Names the main scene class `OutputVideo`.
+- Returns code only, without extra explanation or markdown fences.
+- Handles edge cases gracefully.
+- Uses comments sparingly, only when clarifying complex parts.
+- When in doubt, use Google search effectively to verify facts, functions, or best practices.
+Always ensure your output is precise, accurate, and complete.
+"""
+
     contents = [
+        types.Content(
+            role="system",
+            parts=[types.Part.from_text(text=system_prompt)]
+        ),
         types.Content(
             role="user",
             parts=[types.Part.from_text(text=prompt_text)]
@@ -57,7 +78,6 @@ def generate_manim_code(prompt_text: str, api_key: str) -> str:
 
     return code
 
-
 # ── Manim Code Sanitisation ───────────────────────────────────────────────────
 
 def sanitize_manim_code(raw: str) -> str: