Update app.py

app.py

@@ -16,7 +16,14 @@ MASK_TOKEN = "[MASK]"
 
 vocab = {PAD_TOKEN: 0, MASK_TOKEN: 1}
 
-# Assume vocab, id_to_word, pad_id, mask_id already defined
+# Reverse mapping
+id_to_word = {i: w for w, i in vocab.items()}
+
+# Special token IDs
+pad_id = vocab[PAD_TOKEN]
+mask_id = vocab[MASK_TOKEN]
+
+
 
 # =====================
 # Generation Function