You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
SandboxArea: what it touches
ImprovementsKind: in v2.1.299,
ImprovementsSection of the release
What
On Linux, Claude Code can run commands inside a sandbox, a fenced-off space that limits which files a command can see or change. It is built with a tool called bubblewrap. The way the sandbox handles paths you have blocked has changed:
Paths blocked from reading are now matched exactly as written.
A blocked path that does not exist gets a placeholder only when one can be created. Otherwise Claude Code logs "No placeholder for" that path. Before, a placeholder was always mounted there.
File masks now take precedence over read blocks. A read block at a spot a file mask already covers is skipped.
Setting up the sandbox now stops with an error if the sandbox settings change while blocked paths are being worked out.
Why
This fixes cases where the sandbox failed to start because a blocked path sat in a folder that could not be written to.
