Under the hood
Each artifact now tracks its own sandbox network-access setting, which goes stale after a time limit
What
Claude Code now records, per artifact, whether its sandbox (an isolated execution environment) has network egress (outbound network access) disabled or not. This setting is cached, but after a set age it's treated as unknown rather than trusted, so it must be re-checked.
Why
Caching the setting avoids repeatedly re-checking it, while the staleness cutoff makes sure Claude Code doesn't act on a network-access setting that may no longer be accurate.