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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.20 27 Jan 2026

Enhanced Sandbox Security

What

Significantly improved Unix domain socket security with ownership verification and stale socket cleanup.

Details

Socket directory ownership check: warns if directory owned by different user
Stale socket cleanup: removes sockets for non-running PIDs
Better seccomp filter path discovery for global @anthropic-ai/sandbox-runtime installations
Added .npm-global to seccomp binary search paths
Improved error messages with actionable installation instructions
Warning when seccomp binaries unavailable: "[Sandbox Linux] Seccomp binaries not available - unix socket blocking disabled. Install @anthropic-ai/sandbox-runtime globally for full protection."

Evidence

Socket ownership check at line 523583 ("Socket directory not owned by current user"), stale socket cleanup messages, seccomp search paths at line 95936 (".npm-global"), warning at line 96398

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.20 →