What
When Claude Code verifies the integrity of an extracted package, it now opens each file or directory with a flag that refuses to follow symbolic links, checks that files have exactly one hard link, and strips any group- or world-writable permission bits it finds. The directory-walk integrity check now flags a result as 'tampered' if a file isn't a plain file or fails this new permission check, in addition to the existing 'oversize', 'symlink', and 'reserved' failure outcomes.
Why
This closes off ways a malicious or corrupted package could exploit file permissions, hard links, or symlink tricks during extraction, giving Claude Code a stronger guarantee that extracted files match what was intended.