You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
SandboxArea: what it touches
ImprovementsKind: in v2.1.314,
ImprovementsSection of the release
Unclear It is not clear whether Claude Code reports this reason yet or what triggers it.
What
Claude Code has a list of reasons it can give for refusing to start. A new one, sandbox_required_unavailable, means a working sandbox is required but cannot run in this session. A sandbox is a protected space that limits what commands can reach. Examples are bubblewrap, the Linux sandboxing program, being missing, or the platform not being supported.
Why
Programs that start Claude Code under a policy that requires a sandbox get a clear, machine-readable reason, so they can offer a fix instead of just retrying.
Read from
Names in the bundlesandbox_required_unavailable
How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtIt is not clear whether Claude Code reports this reason yet or what triggers it.
