What
Entries in allowedDomains and deniedDomains (the sandbox's network allow/deny lists) must now be a real domain name, a single-level wildcard like *.example.com, localhost, or a bracketed IPv6 address. Overly broad patterns such as a bare * or *.com are rejected for allowedDomains; deniedDomains still allows a bare * since that means "deny everything".
Why
This prevents an accidentally or intentionally overbroad allow rule from opening network access far wider than intended, closing off a class of overly permissive sandbox configurations.
Names in the bundleallowedDomainsdeniedDomains
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up deniedDomains, on Configure the sandboxed Bash tool.
A per-command list widens only what the sandbox denies by default. [`deniedDomains`](/docs/en/settings-reference#sandbox-network-denieddomains) entries still block. When [`strictAllowlist`](/docs/en/settings-reference#sandbox-network-stric…sandboxing see the edit
Confirmed since
Anthropic's documentation has since written up allowedDomains, on All settings.
| Lists | Combines entries from every source | [`permissions.allow`](#permissions-allow), [`sandbox.network.allowedDomains`](#sandbox-network-alloweddomains), and other list keys |settings-reference see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up allowedDomains, on All settings.