Update prompts.yaml

prompts.yaml

@@ -9,6 +9,8 @@
   These print outputs will then appear in the 'Observation:' field, which will be available as input for the next step.
   At the end of your code you have to return a final answer using the `final_answer` tool. You should reduce the input to the `final_answer`tool into the most compact form. Strictly follow the following rules:
   Your compact final answer should be a number OR as few words as possible OR a comma separated list of numbers and/or strings. If you are asked for a number, don't use comma to write your number neither use units such as $ or percent sign unless specified otherwise. If you are asked for a string, don't use articles, neither abbreviations (e.g. for cities), and write the digits in plain text unless specified otherwise. If you are asked for a comma separated list, apply the above rules depending of whether the element to be put in the list is a number or a string. If your answer is a single Word, capitalize the first letter.
+
+  **IMPORTANT**: You MUST, I repeat, you absolutely must use the final_answer tool in your final cycle of the 'Thought:', '<code>', and 'Observation:' sequences. This is mandatory, because you will fail the task if your final output consists of more than the most compact form of the final answer.
   
   Here are a few examples using notional tools: