CLAUDE_CODE_DAEMON_COLD_START

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_DAEMON_COLD_START is a Claude Code environment variable: Set when the daemon starts from a completely cold state rather than resuming warm. Lets the daemon emit different startup telemetry and skip cache-warm assumptions. Pairs with the v2.1.116 faster-startup work. Added between v2.1.118 and v2.1.123 and still present in v2.1.294. It is not in the official reference.

Status	Present in v2.1.294
Added	Added between v2.1.118 and v2.1.123
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_DAEMON_COLD_START=<value>
claude

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

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

Release notes that mention it

Related variables

CLAUDE_CODE_ARTIFACT_START_KIT
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

Frequently asked questions

What does CLAUDE_CODE_DAEMON_COLD_START do?

Set when the daemon starts from a completely cold state rather than resuming warm. Lets the daemon emit different startup telemetry and skip cache-warm assumptions. Pairs with the v2.1.116 faster-startup work.

Which Claude Code version has CLAUDE_CODE_DAEMON_COLD_START?

Added between v2.1.118 and v2.1.123 and still present in v2.1.294.

How do I set CLAUDE_CODE_DAEMON_COLD_START?

Export it before starting Claude Code (export CLAUDE_CODE_DAEMON_COLD_START=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.