CLAUDE_CODE_PROFILE_STARTUP

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_PROFILE_STARTUP is a Claude Code environment variable: Enable startup profiling; set to 1. Present since v2.1.69 or earlier and still present in v2.1.294. It is not in the official reference.

Status	Present in v2.1.294
Added	Present since v2.1.69 or earlier
Category	Debugging
Official docs	Not listed

How to set it

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

export CLAUDE_CODE_PROFILE_STARTUP=<value>
claude

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

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

Release notes that mention it

Related variables

ANTHROPIC_PROFILE
CLAUDE_CODE_PROFILE_QUERY: Likely merged into general profiling.
CLAUDE_AI_PROFILE_SCOPE
ANTHROPIC_LOG: SDK internal logging level.
CLAUDE_CODE_COMMIT_LOG: Likely controls whether or where Claude Code logs commit operations.
CLAUDE_CODE_DEBUG_LOG_LEVEL: Set debug logging verbosity level.
CLAUDE_CODE_DEBUG_LOGS_DIR: Custom directory for debug logs.
CLAUDE_CODE_DEBUG_REPAINTS: Enables debug logging for terminal repaint operations.

Frequently asked questions

What does CLAUDE_CODE_PROFILE_STARTUP do?

Enable startup profiling; set to 1

Which Claude Code version has CLAUDE_CODE_PROFILE_STARTUP?

Present since v2.1.69 or earlier and still present in v2.1.294.

How do I set CLAUDE_CODE_PROFILE_STARTUP?

Export it before starting Claude Code (export CLAUDE_CODE_PROFILE_STARTUP=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.