Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.277 ·

Sandbox rules now merge startup read rules with runtime rules, plus new startup_read_rules telemetry

Sandbox rule resolution now merges startup read rules with runtime rules, and reports a startup_read_rules count

TierUnder the hoodhow much it should matter to you
Useful2my rating, 1 to 5
Signal2worth watching, 1 to 5
AreaSandboxwhat it touches
KindInternal Changesin v2.1.277,
Under the hood

Sandbox rule resolution now merges startup read rules with runtime rules, and reports a startup_read_rules count

What

Claude Code's sandbox (the restricted environment tool calls run inside) now combines a set of startup read rules with the runtime rules it already computed, instead of returning only the runtime set. Telemetry for this process also now reports a startup_read_rules count.

Why

This means the sandbox's effective rule set reflects permissions established at startup as well as those computed while running, so reads that were allowed at startup should no longer be missed when rules are resolved later in a session.

See this entry in the whole of v2.1.277 →