Edit refuses devices and pipes and handles files that report zero size

Edit is the tool Claude uses to change a file. It now checks what kind of file it was given:

• Devices, FIFOs (named pipes) and sockets are refused with a message saying Edit only changes regular files.
• Files that report a size of zero, such as files under /proc, are read up to a size limit.
• A zero-size file whose content goes over that limit is refused as too large.
• A file with no data yet gets an error saying it may be a stream.