Simon Willison’s Weblog

27th July 2025

TIL: Exception.add_note (via) Neat tip from Danny Roy Greenfeld: Python 3.11 added a .add_note(message: str) method to the BaseException class, which means you can add one or more extra notes to any Python exception and they'll be displayed in the stacktrace!

Here's PEP 678 – Enriching Exceptions with Notes by Zac Hatfield-Dodds proposing the new feature back in 2021.