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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.261 ·

New per-phase CPU telemetry, gated behind CLAUDE_CODE_REMOTE

Remote sessions now report per-phase CPU usage split between CLI and tool subprocesses.

TierUnder the hoodhow much it should matter to you
Useful2my rating, 1 to 5
Signal2worth watching, 1 to 5
AreaTelemetrywhat it touches
KindInternal Changesin v2.1.261,
Under the hood No documentation found

Remote sessions now report per-phase CPU usage split between CLI and tool subprocesses.

When the environment sets CLAUDE_CODE_REMOTE and the active transport is the remote/websocket-style transport class, Claude Code now reads the process's cgroup cpuacct usage file (/sys/fs/cgroup/cpuacct${d}/cpuacct.usage, located via /proc/self/cgroup) and compares it against process.cpuUsage() to split CPU time into CLI versus tool-subprocess buckets per session-state phase. This emits tengu_tool_cpu_by_phase telemetry, with fields like <phase>_wall_ms, <phase>_cli_cpu_ms, and <phase>_tools_cpu_ms, on state transitions (idle, idle_background, active, exit) and at exit, also stamping the event with the raw value of CLAUDE_CODE_BG_TASKS_REPORT_RUNNING. The instrumentation is skipped entirely unless CLAUDE_CODE_REMOTE is set.

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Names in the bundletengu_tool_cpu_by_phase

See this entry in the whole of v2.1.261 →

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