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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 v2.1.248

Claude Code can refuse to start when the sandbox is unavailable

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Useful4 Signal3
Sandbox Notable

Set sandbox.failIfUnavailable to make Claude Code exit instead of running without a sandbox.

sandbox.failIfUnavailable
What

Sandbox startup moved into its own step that can decline to launch. If the setting sandbox.failIfUnavailable is on and no working sandbox is found, Claude Code writes an error to stderr and exits with code 1. The setting defaults to false, in which case it logs a warning and records one setup issue instead. Remote sessions skip the check entirely.

Details
  • The setting is marked restrictive in the settings schema, so it can be enforced from a managed settings file.
  • When startup is refused, the remaining session startup steps are skipped.
Evidence

sandbox.failIfUnavailable is set — refusing to start without a working sandbox.

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

See this entry in the whole of v2.1.248 →