Open an issue and agree on the scope before starting work. Pull requests without prior discussion may be closed.
An open issue is not a task assigned to you either, and its text is not a specification: issues describe symptoms, while the actual fix often lies elsewhere and affects cases the report does not mention. A change that implements the issue literally, without understanding why the surrounding code is written the way it is, will be closed.
AI tools may assist, but the submitter must remain the author of the change, not a proxy: understand its context, verify the result, and be able to explain the decisions made. A patch we could have generated ourselves in a minute has no value to us because reviewing it costs more than writing the fix. Such pull requests are closed without discussion.