Update README.md

README.md

@@ -296,6 +296,12 @@ print(tokenizer.apply_chat_template(chat, tokenize=False))
   date: 2021-01-01
   url: https://web.site/123
   ```
+
+  You can also add an instruction similar to the following, to have a more deterministic response when the context doesn't provide an answer to the question:
+
+  ```text
+  If you don't know, respond with "IRRELEVANT"
+  ```
 </details>
 
 <details>