You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
NotebooksArea: what it touches
ImprovementsKind: in v2.1.296,
ImprovementsSection of the release
What
UTF-8 is the standard way of storing text as bytes. Some files use an older encoding (such as Windows-1252, Shift-JIS or GBK) or are not text at all. When NotebookEdit, the tool Claude uses to edit Jupyter notebooks, finds a notebook like this, it now stops and writes nothing. Before, it decoded the file as best it could, which can garble characters, and saved the result as UTF-8.
The error tells Claude that the file is not valid UTF-8 and suggests using a shell command or asking you about converting the file.
There is also a similar message for Write. It covers new content that contains the replacement character (U+FFFD, the symbol that stands in for text that could not be read) when the file already on disk is not valid UTF-8.
Why
Files saved in an older encoding are no longer silently damaged when Claude edits them. You get a clear refusal instead and can decide how to handle the file.
