Under the hood
Background task status messages now sanitize task fields before inserting them into the model's reminder text
What
When Claude Code reports the status of a background task or agent (running, stopped, a summary of changes, or an output path) back to the model as a system reminder, the task's description, id, type, and delta summary now pass through a sanitizing function before being inserted into that text.
Why
This guards against task data containing content that could otherwise be inserted unsafely into the text sent to the model.