CLAUDE_CODE_THREAD_CPU_ONE_IN

Updated November 6, 2026 by Alex Sorokoletov

CLAUDE_CODE_THREAD_CPU_ONE_IN is a Claude Code environment variable: Runs the thread CPU timing sample for about one in N remote sessions; set to 0 to disable it, and a non-integer value falls back to a built-in default. Added in v2.1.319 and still present in v2.1.319. It is not in the official reference.

Status	Present in v2.1.319
Added	Added in v2.1.319
Category	Other
Official docs	Not listed

How to set it

For one session, export it in the shell that starts Claude Code:

export CLAUDE_CODE_THREAD_CPU_ONE_IN=<value>
claude

To apply it to every session, add it to the env object of a settings file:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CODE_THREAD_CPU_ONE_IN": "<value>"
  }
}

Related variables

CLAUDE_CODE_HOOKS_SAME_THREAD: Runs plugin hooks on the same thread instead of in a worker when set; the default is worker.
ANTHROPIC_BETAS: Comma-separated beta feature headers.
ANTHROPIC_CUSTOM_HEADERS: Custom HTTP headers (newline-separated Key: Value).
ANTHROPIC_FEDERATION_RULE_ID
ANTHROPIC_ORGANIZATION_ID
ANTHROPIC_WORKSPACE_ID
BETA_TRACING_ENDPOINT: Custom endpoint for beta tracing.
CLAUDE_AFK_COUNTDOWN_MS: Milliseconds before the away-from-keyboard timeout at which the warning countdown begins; defaults to 20000 and is capped at the timeout length.

Frequently asked questions

What does CLAUDE_CODE_THREAD_CPU_ONE_IN do?

Runs the thread CPU timing sample for about one in N remote sessions; set to 0 to disable it, and a non-integer value falls back to a built-in default.

Which Claude Code version has CLAUDE_CODE_THREAD_CPU_ONE_IN?

Added in v2.1.319 and still present in v2.1.319.

How do I set CLAUDE_CODE_THREAD_CPU_ONE_IN?

Export it before starting Claude Code (export CLAUDE_CODE_THREAD_CPU_ONE_IN=value), or add it to the "env" object in ~/.claude/settings.json to apply it to every session.

All variables, searchable: Claude Code environment variables.