Update app.py

app.py

@@ -16,7 +16,28 @@ Exclude any text that has been cut, striked, or crossed out (since these may rep
 Clearly distinguish between a "step cut" and when variables cancel out during a step.
 
 Present the transcription neatly without including unnecessary markings. """
-GRADING_PROMPT = """ You are an official examiner. Grade the student transcription using the question paper and the official marking scheme. Rules: 1. Apply marks exactly as per the markscheme (M1, A1, etc.). 2. M marks must be earned before A marks. 3. Justify each awarded or withheld mark with clear reasoning. 4. Classify all errors as Conceptual Error, Silly Mistake, or None. 5. Follow dependency between M and A strictly. 6. Do not give marks outside the markscheme. Output must be a structured grading report with reasoning. """
+GRADING_PROMPT = """ Instructions to Examiners:
+Abbreviations:
+- M: Marks for correct Method.
+- A: Marks for Answer or Accuracy (often depends on preceding M mark).
+- R: Marks for clear Reasoning.
+- AG: Answer given in the question; no marks awarded.
+- FT: Follow Through; award marks for correct method/answer using incorrect earlier results.
+
+Marking Rules:
+1. Always follow the markscheme annotations (M1, A2, etc.).
+2. M marks must be earned before dependent A marks are awarded (no M0 followed by A1 unless explicitly allowed).
+3. If M and A marks are on the same line (e.g., M1A1), M is for the method attempt, A is for correct values.
+4. Multiple A marks on the same line are awarded independently unless otherwise noted.
+5. Do not split M2, A3, etc. unless instructed.
+6. "Show that" responses do not need to restate the AG line unless noted.
+7. Once a correct answer is seen, ignore further incorrect working unless it affects a later part (then apply FT as appropriate).
+8. Do not award the final A mark if an incorrect approximation is used in the same part.
+
+Error Avoidance:
+- **No incorrect mark allocation:** Do not award marks unless they are explicitly justified by the markscheme.
+- **No misclassification of errors:** Distinguish correctly between "Conceptual Errors" and "Silly Mistakes."
+- **Follow markscheme logic exactly:** Especially regarding when to withhold accuracy marks if method marks are not earned."""
 
 # ---------- HELPER: Save to PDF ----------
 def save_as_pdf(text, filename="output.pdf"):