Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
TelemetryArea: what it touches
Internal ChangesKind: in v2.1.312,
Internal ChangesSection of the release
What
Claude Code could already read shell CPU time from the cgroup file cpuacct.usage. A cgroup is a Linux feature that groups processes and tracks the resources they use. That figure is now captured at the start of each turn and reported per turn. A turn is one round of Claude working on your request.
The turn timing now carries a shellCpu object with turnMs and sinceLastResult.
The result schema gains three optional internal fields: shell_cpu_ms_turn, shell_cpu_ms_since_last_result and shell_wall_ms_since_last_result. These are CPU time for the turn, CPU time since the last result, and elapsed clock time since the last result.
The figures cover shells started by the Bash and Monitor tools, the tools Claude uses to run commands.
They come from a Linux cgroup v1 cpuacct group. When there is no such group, the fields are left out.
Why
This is internal measurement of how much processing time shell commands use. You do not see it in the interface and nothing about how commands run changes.
